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Alessandro Catanzaro, Armando Genco, Charalambos Louca, David A. Ruiz‐Tijerina, Daniel J. Gillard, Luca Sortino, Aleksey Kozikov, Evgeny M. Alexeev, Riccardo Pisoni, Lee Hague, [Kenji Watanabe](https://orcid.org/0000-0003-3701-8119), [Takashi Taniguchi](https://orcid.org/0000-0002-1467-3105), Klaus Ensslin, Kostya S. Novoselov, Vladimir Fal'ko, Alexander I. Tartakovskii

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[Resonant Band Hybridization in Alloyed Transition Metal Dichalcogenide Heterobilayers](https://mdr.nims.go.jp/datasets/a1231507-85e8-4763-9489-52b090cbe019)

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Resonant Band Hybridization in Alloyed Transition Metal Dichalcogenide HeterobilayersRESEARCH ARTICLEwww.advmat.deResonant Band Hybridization in Alloyed Transition MetalDichalcogenide HeterobilayersAlessandro Catanzaro, Armando Genco,* Charalambos Louca,* David A. Ruiz-Tijerina,*Daniel J. Gillard, Luca Sortino, Aleksey Kozikov, Evgeny M. Alexeev, Riccardo Pisoni,Lee Hague, Kenji Watanabe, Takashi Taniguchi, Klaus Ensslin, Kostya S. Novoselov,Vladimir Fal’ko, and Alexander I. Tartakovskii*In memory of Alessandro CatanzaroBandstructure engineering using alloying is widely utilized for achievingoptimized performance in modern semiconductor devices. While alloying hasbeen studied in monolayer transition metal dichalcogenides, its application invan der Waals heterostructures built from atomically thin layers is largelyunexplored. Here, heterobilayers made from monolayers of WSe2 (or MoSe2)and MoxW1 − xSe2 alloy are fabricated and nontrivial tuning of the resultantbandstructure is observed as a function of concentration x. This evolution ismonitored by measuring the energy of photoluminescence (PL) of theinterlayer exciton (IX) composed of an electron and hole residing in differentmonolayers. In MoxW1 − xSe2/WSe2, a strong IX energy shift of ≈100 meV isobserved for x varied from 1 to 0.6. However, for x < 0.6 this shift saturatesand the IX PL energy asymptotically approaches that of the indirect bandgapin bilayer WSe2. This observation is theoretically interpreted as the strongvariation of the conduction band K valley for x > 0.6, with IX PL arising fromthe K − K transition, while for x < 0.6, the bandstructure hybridizationbecomes prevalent leading to the dominating momentum-indirect K − Qtransition. This bandstructure hybridization is accompanied with strongmodification of IX PL dynamics and nonlinear exciton properties. This workprovides foundation for bandstructure engineering in van der Waalsheterostructures highlighting the importance of hybridization effects andopening a way to devices with accurately tailored electronic properties.A. Catanzaro, A. Genco, C. Louca, D. J. Gillard, L. Sortino, E. M. Alexeev,A. I. TartakovskiiDepartment of Physics and AstronomyThe University of SheffieldSheffield S3 7RH, UKE-mail: armando.genco@polimi.it; charalambos.louca@polimi.it;a.tartakovskii@sheffield.ac.ukThe ORCID identification number(s) for the author(s) of this articlecan be found under https://doi.org/10.1002/adma.202309644© 2024 The Authors. Advanced Materials published by Wiley-VCHGmbH. This is an open access article under the terms of the CreativeCommons Attribution License, which permits use, distribution andreproduction in any medium, provided the original work is properly cited.DOI: 10.1002/adma.2023096441. IntroductionVan der Waals stacking allows unprece-dented possibilities in combining differ-ent atomically thin materials within asingle device as well as tuning of theirproperties, by selecting different mono-layer materials or by varying their rel-ative twist angle. Thus, van der Waals(vdW) heterostructures made from ver-tically stacked atomically thin transitionmetal dichalcogenides (TMDs) present apowerful platform for development of noveldevices with widely tuneable properties[1–3]as well as for gaining new insights in thephysics of excitons[4–8] and emergent exci-tonic and quantum phenomena in moirésuperlattices.[9–17] Most of the structuresstudied so far (such as stacked monolayersof MoSe2 and WSe2) were so-called type-II semiconducting heterostructures,[18] ex-hibiting the maximum of the valence andthe minimum of the conduction bandsin the adjacent layers. A prominent fea-ture in type-II TMD heterostructures isthe formation of interlayer excitons (IX)A. Genco, C. LoucaDipartimento di FisicaPolitecnico di MilanoPiazza Leonardo da Vinci, 32, Milano 20133, ItalyD. A. Ruiz-TijerinaDepartamento de Física QuímicaInstituto de Física, Universidad Nacional Autónoma de MéxicoCiudad de México, C.P., 04510 Mexico, MéxicoE-mail: d.ruiz-tijerina@fisica.unam.mxL. SortinoChair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of PhysicsLudwig-Maximilians-Universität München80539 Munich, GermanyA. Kozikov, V. Fal’koDepartment of Physics and AstronomyUniversity of ManchesterManchester M13 9PL, UKAdv. Mater. 2024, 36, 2309644 2309644 (1 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbHhttp://www.advmat.demailto:armando.genco@polimi.itmailto:charalambos.louca@polimi.itmailto:a.tartakovskii@sheffield.ac.ukhttps://doi.org/10.1002/adma.202309644http://creativecommons.org/licenses/by/4.0/http://creativecommons.org/licenses/by/4.0/mailto:d.ruiz-tijerina@fisica.unam.mxhttp://crossmark.crossref.org/dialog/?doi=10.1002%2Fadma.202309644&domain=pdf&date_stamp=2024-02-13www.advancedsciencenews.com www.advmat.dewith a hole and electron confined in different layers. The IX PL,although observed most clearly at cryogenic temperatures, hasproven to be a sensitive probe of the novel physics in semicon-ducting van der Waals heterostructures,[19,20] and will be utilizedin our work to monitor the properties of the studied TMD heter-obilayers.As well as the use of heterostructures, another very powerfulapproach for accurate tailoring of the properties of semiconduc-tor devices is the use of alloyed semiconductors. This approachhas been successfully applied in numerous applications, fromlasers to few-nm-sized transistors using traditional III-V, II-VI,and group IV semiconductors.[21] This approach allows gradualtuning of bandgaps as well as the whole bandstructure, allowingto control carrier confinement and thus influence their transportand optical properties. Numerous semiconducting alloys of lay-ered materials have been demonstrated in the monolayer formachieved both by direct synthesis and exfoliation from bulk,[22] in-cluding MoxW1 − xSe2 used in this work, where alloying was usedto control the valley polarization properties.[23,24] More recently,alloying was successfully employed to tune the energy of in-terlayer excitons[25] in WS2(1 − x)Se2x/WSe2, and a direct–indirectband transition in Mo1 − xWxS2/MoSe2 heterostructures has beenpredicted theoretically.[26]In our work we study MoxW1 − xSe2/WSe2 andMoxW1 − xSe2/MoSe2 heterostructures built from stackedTMD monolayers in a wide range of composition x (Figure 1a).In MoxW1 − xSe2/WSe2, we demonstrate tuning of ≈130 meVof the IX photoluminescence (PL) peak energy as a function ofx displaying two types of behavior: a fast tuning by ≈100 meVfor x > 0.6 followed by an asymptotic dependence for x < 0.6,where the IX PL energy asymptotically approaches that of theA. KozikovSchool of Mathematics, Statistics and PhysicsNewcastle UniversityNewcastle upon Tyne NE1 7RU, UKE. M. AlexeevCambridge Graphene CentreUniversity of Cambridge9 J. J. Thomson Avenue, Cambridge CB3 0FA, UKR. Pisoni, K. EnsslinSolid State Physics Laboratory, ETH ZurichZurich CH-8093, SwitzerlandL. HagueNational Graphene Institute, University of ManchesterManchester M13 9PL, UKK. WatanabeResearch Center for Electronic and Optical MaterialsNational Institute for Materials Science1-1 Namiki, Tsukuba 305-0044, JapanT. TaniguchiResearch Center for Materials NanoarchitectonicsNational Institute for Materials Science1-1 Namiki, Tsukuba 305-0044, JapanK. S. NovoselovInstitute for Functional Intelligent MaterialsNational University of SingaporeSingapore 117546, SingaporeV. Fal’koHenry Royce Institute for Advanced MaterialsUniversity of ManchesterManchester M13 9PL, United Kingdomindirect bandgap in bilayer WSe2. A similar but less pronouncedtuning and saturation at the indirect bandgap of bilayer MoSe2is observed for MoxW1 − xSe2/MoSe2. In MoxW1 − xSe2/WSe2,concurrent with the transition between the two types of be-havior, we also observe strong changes in the IX PL dynamicsand intensity: the PL lifetime shortens and intensity stronglydecreases for x < 0.6. The strong changes are also observed inthe power dependence of IX PL, where a typical blue-shift of theIX PL peak[18] is strongly suppressed for x < 0.6. Our theoreticalanalysis shows that the observed changes in the behavior occurdue to the bandstructure hybridization, leading to the shift ofthe conduction band minimum in the heterobilayer from Kto Q valley for x ≈ 0.6. The observed behavior thus signifiesthe transition from the K − K configuration of the valence toconduction band transition for x > 0.6 to the K − Q configurationfor x < 0.6.2. ResultsA set of 15 samples was studied, including heterobilayers (HBLs)either fully encapsulated in hBN flakes or alternatively placedon a relatively thick (of the order of 50 nm) hBN. The TMDHBLs were fabricated from monolayers mechanically exfoliatedfrom bulk crystals. The alloy bulk crystals were provided byHQ Graphene, where the material composition was accuratelymeasured in each bulk sample using energy dispersive X-ray(EDX) microanalysis. The majority of HBLs were made with theprominent crystal edges aligned within 0.5° accuracy, constitut-ing structures with either near 0° or 60° crystal axis rotation (re-ferred to as R- and H-stacking, respectively). For further exper-iments we did not differentiate between R- and H-stacked het-erobilayers and measured all fabricated samples. However, ourresults imply that inadvertently the majority of samples that wefabricated and studied were of the H-stacking configuration. Tounderstand why the yield of fabricated structures may have a ten-dency toward one of the two orientations we go over the fabrica-tion process in more detail in Note S1 (Supporting Information).It is likely that the close to 60° or 0° alignment in ourHBL samples results in realization of the regime of latticereconstruction.[27–30] However, the method that we adopted forreporting our PL data (summarized in Figure 2c) by averagingPL spectra over 20–60 different locations on each measured HBL,masks the influence of lattice reconstruction on exciton proper-ties, for which we instead refer the reader to Ref. [30]. We alsonote that lattice reconstruction influences the local shifts of theIX energy.[28–30] However, these shifts are smaller than the IX andband-edge energy shifts as a function of concentration x, and thusonly provide a detail in the overall trends of bandstructure mod-ifications with alloy concentration, which we report here.A schematic of a generic MoxW1 − xSe2/WSe2 HBL is displayedin Figure 1b, also showing IX formation with a hole localizedin WSe2 and the electron in the alloy. A bright field (BF) micro-scope image of a Mo0.85W0.15Se2/WSe2 heterostructure is shownin Figure 1c. The alloy monolayer area is highlighted with redlines, while the edges of the WSe2 flake are shown in green.Figure 1d shows a PL image of this sample measured at roomtemperature showing in yellow bright emission from the uncou-pled monolayer WSe2 and in purple dimmer emission from theuncoupled monolayer Mo0.85W0.15Se2. Notably lower PL intensityAdv. Mater. 2024, 36, 2309644 2309644 (2 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.de1.3 1.4 1.5 1.6 1.702x104PLintensity(cts/s)Energy (eV)1x1043x1044x104abcd fe gMo0.85W0.15Se2 /WSe2MoxW1-xSe2MoxW1-xSe2     alloyWSe2WSe2Figure 1. Van der Waals heterostructures based on TMD alloy monolayers. a) Energy level diagram for a type-II heterojunction formed by WSe2 andMoxW1 − xSe2 monolayers. Direct excitons (DX) form in each layer, while interlayer excitons (IX) are created between electrons in the conduction band(CB) of the alloy and holes in the valence band (VB) of WSe2. The IX energy is tuned by changing the Mo composition x in the alloy. b) Schematic ofthe alloy HBL showing the IX electric dipole moment orientated perpendicular to the plane of the monolayers. c) Bright-field (BF) microscope image ofthe HBL. The red line shows the Mo0.85W0.15Se2 flake while the green line shows the WSe2 flake. d) PL image of the HBL taken at room temperature.PL quenching in the HBL region indicates efficient charge transfer between the monolayers. e) Low temperature (T = 10 K) PL map of the HBL in thespectral region of IX PL (1.3–1.45 eV). Bright IX PL is detected from the HBL only. f) Low temperature (10 K) PL map of the HBL in the spectral regionof DX PL (1.45–1.7 eV). Scale bars for (c–f) 10 μm. g) Low temperature (10K) spectrum measured for a Mo0.85W0.15Se2 HBL.is observed in the heterobilayer region where the two monolayersoverlap. This arises from the quenching of the PL of the intralayerexciton (referred to below as DX) due to the efficient chargetransfer between the layers. This shows efficient electronic cou-pling between the TMD monolayers, and confirms the formationof a type-II heterostructure.[31–33]Figure 1e,f shows PL maps of the same HBL acquired at a cryo-genic temperature T = 10 K. The maps show integrated PL inten-sity in the spectral ranges 1.3–1.45 eV in Figure 1e and 1.45–1.7eV in Figure 1f. These ranges are selected based on the low tem-perature PL spectra, with a typical example measured in the HBLarea shown in Figure 1g. In addition to a strong peak ≈1.6 eVcorresponding to the intralayer exciton (DX) in Mo0.85W0.15Se2and some lower intensity features arising from WSe2, additionalpeaks are observed at low energy (labeled IX). These peaks corre-spond to the interlayer exciton PL and are only observed withinthe HBL area.Before describing the properties of HBLs comprising alloymonolayers, we briefly report optical properties of monolayerand bilayer alloy TMDs themselves. Figure 2a shows PL spec-tra for MoxW1 − xSe2 alloy monolayers with different composi-tion x. For 0.49 ⩽ x ⩽ 1, the PL spectra closely resemble that ofMoSe2 with two narrow peaks attributed to neutral exciton, X0(the spectral feature of A-exciton) and the corresponding chargedexciton or trion, X*. For x ⩽ 0.38, the PL peaks become muchbroader, the X* peak becomes much less pronounced, and morefeatures appear at lower energies. This behavior is observed forconcentrations for which the lowest neutral exciton state in thealloy transforms from optically bright as in MoSe2 to opticallydark as in WSe2, as previously predicted.[23,34] We have furtherstudied reflectance contrast (RC) spectra from monolayers thatallows detection of high energy states, for example, B-excitons(see Note S2, Supporting Information). The A-exciton energy ap-pears almost constant at 1.650 eV for 0.49 ⩽x ⩽ 1 with a weak in-crease toward x = 1. For x < 0.49, the energy of A peak increaseseventually reaching 1.742 eV for monolayer WSe2. The observedtrend can be fitted by the quadratic Vegard’s law (Note S2, Sup-porting Information; Figure 2c), adopted, for example, for alloysof III-V semiconductors,[35] revealing a bowing parameter b =0.16, in close agreement with previous reports.[36,37] Figure S2(Supporting Information) shows that the B-exciton energy in-creases more sharply with decreasing x from 1.877 to 2.185 eVsignifying a strong increase in the valence band spin-orbit split-ting as the A-B exciton splitting changes from ≈230 to ≈340 meV.Of high relevance to HBL studies presented in this work wehave also measured low T PL and RC for exfoliated MoxW1 − xSe2bilayers with different concentration of x (see Note S3, Support-ing Information). The RC spectra show a similar behavior of Aand B exciton energies compared to monolayers. In Figure 2c,we show a comparison between the A exciton peak positions inmonolayers (diamonds) and bilayers (triangles), where similarparabolic trends are observed. However, a systematic red-shiftup to 40 meV of the peak positions with respect to the mono-layers with the same x occurs.[38] The PL data shows that themomentum-indirect transition is always dominant in bilayers(Note S3, Supporting Information), with its energy tuned by >100 meV by changing the Mo composition of the bilayer alloyMoxW1 − xSe2.Adv. Mater. 2024, 36, 2309644 2309644 (3 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.de1.60 1.65 1.70 1.75NormalizedPLintensity(a.u)Energy (eV)x=0.21x=0.33x=0.38x=0.49x=0.64x=0.71x=0.85x=0.93X01L MoSe21L WSe2X*1.3 1.4 1.5 1.6NormalizedPLintensity(a.u)MoSe2/WSe2x=0.93x=0.85x=0.71x=0.64x=0.49x=0.38x=0.33x=0.212L WSe2Energy (eV)1L  MoxW1- xSe20.0 0.2 0.4 0.6 0.8 1.01.301.351.401.451.501.551.601.651.701.751.80 X0 in 1L MoxW1-x Se2Energy(eV)Composition x in MoxW1- xSe2/WSe2X0 in 2L MoxW1-x Se2IX1  in MoxW1-x Se2/WSe2IX2  in MoxW1-x Se2/WSe2HS  MoxW1- xSe2/WSe2a b cWSe2WSe2WSe2MoSe2X*X0IX2IX1Figure 2. Optical spectra of intralayer and interlayer excitons in alloy monolayers and heterostructures. a) Normalized PL spectra measured at T = 10Kof MoxW1 − xSe2 alloy monolayers with different Mo concentrations (x), showing the neutral exciton X0 and the trion X* peaks. b) Normalized PL spectraof the MoxW1 − xSe2/WSe2 HBLs measured at 10K for different x. IX1 and IX2 label the interlayer exciton PL and the PL peak at the indirect bandgap inWSe2 bilayers, respectively. c) Solid (open) squares show spectral positions of IX1 (IX2) PL peaks in the alloy/WSe2 HBLs. See text for discussion ofthe x =0.21 HBL. Error bars show the spread in energy of multiple IX transition peaks measured in several HBL samples (see text for further details).Diamonds (triangles) show X0 (A-exciton) peak position in alloy monolayers (bilayers) measured using reflectance contrast. Solid light blue and redlines are parabolic fits of the A-exciton peak energy in alloy monolayers and bilayers, respectively. The dashed red and blue horizontal lines correspondto the IX1 PL peak in MoSe2/WSe2 HBLs and the IX2 PL peak in WSe2 homobilayers, respectively.We now discuss the tuning of the interlayer exciton energyin MoxW1 − xSe2/WSe2 HBLs as a function of x. Figure 2bshows normalized PL spectra measured for such structures atT = 10 K in the energy range where IX PL is expected, as iden-tified in Figure 1. Similarly to Figure 1g, features correspondingto IX PL can be readily identified in the spectra of all structureswith x ⩾0.21. Following the approach depicted in Figure 1, wemeasured PL maps at low temperature on all the structures toensure that these features could be observed only in the regionswhere the two TMDs overlap (see Note S4, Supporting Informa-tion). For all HBLs with x >0.33, IX PL shows a spectrum withtwo or more peaks, similar to those reported for MoSe2/WSe2heterostructures.[11,18,30,39,40] The energies of these PL peaks in-crease with decreasing x (see further peak analysis of the IXspectra and a detailed discussion of the origin of the differentspectral features in Note S5, Supporting Information). The tun-ing is pronounced for x up to 0.64 and exceeds 100 meV, butthen slows down and is less than 50 meV for the whole range ofx < 0.64.For x = 0.33, these peaks practically merge into a single peak at≈1.5 eV. For x = 0.21, a peak at ≈1.51 eV provides a continuationof this trend, while new structured PL appears at higher energyat and above 1.54 eV. Similar high energy PL peaks are also ob-served at ≈1.54 and 1.57 eV in the natural (as exfoliated) WSe2bilayer[41] (see the spectrum labeled 2L in the figure), while nodiscernible PL occurs in this sample at lower energies, where IXPL is observed in samples with x > 0. Except for the IX feature at≈1.51 eV in the x = 0.21 structure, the spectra for the structureswith x = 0.21 and x = 0 are similar to the one reported for anotherWSe2 bilayer in Figure S3 (Supporting Information), measuredon a different sample.Spectra similar to the ones reported in Figure 2b were mea-sured on 20 to 60 points across each HBL. Notably, the PL inten-sity averaged across the measured points of each HBL drops sig-nificantly for x < 0.6 (see Note S6, Supporting Information). Forsome values of x, we also made several samples where similar PLmeasurements were carried out at multiple positions providingsimilar results.We note that PL data reported in Figure 2b show qualitativelydifferent spectra for different samples. Whereas the x = 0.93 andx = 0.38 samples show a two-peak structure with the low-energypeak exhibiting higher PL intensity, other samples exhibit two-peak PL spectra with a more pronounced high-energy peak (seefurther details of the fitting in Figure S8, Supporting Informa-tion). This may indicate that the x = 0.93 and x = 0.38 sampleshave a different stacking configuration from the rest.[30,42] To fur-ther explore this possibility, in Note S5 (Supporting Information),we present an explanation of the two-peak structure found in ourinterlayer exciton PL measurements of Figure 2b supporting ouroverall conclusion that most of the structures studied in this workhad a 60° mutual rotation of the alloy and WSe2 monolayers,i.e., displayed the H-stacking, which we believe was a result ofspecifics of the fabrication procedure described in Note S1 (Sup-porting Information).Adv. Mater. 2024, 36, 2309644 2309644 (4 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.de1.0 0.8 0.6 0.4 0.2 0.00.1110IXLifetime( ns)x Mo composition in alloyIRF resolution0 20 40 60 80051015 MoSe2 / WSe2x=0.71x=0.49x=0.212L WSe2IXΔE(meV)Power (μW )cba0 5 10 15 202L WSe2x = 0.21x = 0.49x = 0.71MoSe2/WSe2IXNormalizedPLIntensity(a.u.)Time (ns)Figure 3. Time-resolved and power-dependent PL of interlayer excitons in MoxW1 − xSe2/WSe2 heterostructures. a) Time-resolved PL traces of IX inMoxW1 − xSe2/WSe2 HBLs with different x measured at T = 10 K. Fitting with a single (x = 1, 0.49) or double (x = 0.71, 0.21, 0) exponential decay areshown with black lines. b) IX PL decay times as a function of x for MoxW1 − xSe2/WSe2 HBLs extracted from the data in (a). The dashed line indicates thetemporal resolution limit given by the instrument response function (IRF) of the experimental setup. c) Energy shift of the IX peak in MoxW1 − xSe2/WSe2HBLs with different x as a function of the excitation power.The PL peak positions averaged over many measurements atdifferent locations within each HBL are presented in Figure 2c.Here the squares show the average high energy peak posi-tion of the IX1 PL (EIX), ascribed in MoSe2/WSe2 HBLs to themomentum-direct K-K transition.[11,39,40] The vertical bars showthe spectral extension of the PL intensity within a standard de-viation from the average intensity, covering all the features ob-served in the spectra near the IX energy. Overall, we observethat EIX changes with decreasing x by 130 meV from 1.38 eV forMoSe2/WSe2 to 1.51 eV for Mo0.21W0.79Se2/WSe2. This is in con-trast to a weak dependence of the MoxW1 − xSe2 bandgap (as canbe deduced from a weak dependence of the X0 exciton energypresented in the same plot) for 0.5 < x ⩽ 1. Thus, in this rangeof x the conduction band offset of MoxW1 − xSe2 with respect tothat of WSe2 evidently experiences a much faster change, witha shift by more than 100 meV, as can be deduced from the in-crease of EIX (assuming weak dependencies of the IX and DXexciton binding energies on x).[43] It is seen from Figure 2c thatthe dependence of EIX on x is nonlinear and asymptotically ap-proaches 1.51 eV, close to the energy of the exciton transition atthe indirect bandgap in the homobilayer of WSe2 marked IX2 inFigure 2b and shown with open squares in Figure 2c.We also fabricated several MoxW1 − xSe2/MoSe2 HBLs, wherea more complicated behavior is observed for 0.33 < x ⩽ 1,with less distinct PL peaks in the range where IX PL is ex-pected (see Note S7, Supporting Information). However, withincreasing x, the main feature of the low energy PL responseasymptotically approaches the energy corresponding to PL atthe indirect bandgap in homobilayer MoSe2, similarly to theMoxW1 − xSe2/WSe2 HBLs.In order to understand the nature of the low energy PL peaks inthe studied HBLs and to gain further insight in the properties ofthe IX as a function of the alloy composition, we carried out time-resolved and power-dependent PL measurements. The transientPL decay signals measured for MoxW1 − xSe2/WSe2 HBLs areshown in Figure 3a. Each transient PL decay curve is measuredat the IX1 PL peak shown in Figure 2c. For Mo0.21W0.79Se2/WSe2structure, we measure at the energy of 1.51 eV corresponding tothe energy of IX1 (solid square in Figure 2c). For the WSe2 bi-layer the measurement is carried out at the PL peak around 1.55eV (IX2, open squares in Figure 2c).It can be observed that the PL decay of the IX shortens pro-gressively, decreasing from tens of nanoseconds in MoSe2/WSe2down to hundreds of picoseconds in the Mo0.21W0.79Se2/WSe2HBL and bilayer WSe2. The lifetime values extracted from ex-ponential fits of the time-resolved PL curves are summarized inFigure 3b as a function of the alloy composition (see further de-tails on the results of the fitting in Note S8, Supporting Informa-tion). As the alloys gradually become more chemically similar toWSe2, the PL lifetime decreases by more than two orders of mag-nitude, with the most abrupt change occurring for x < 0.4. Thefast decay times extracted for the WSe2 bilayer are limited by theAdv. Mater. 2024, 36, 2309644 2309644 (5 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.detemporal resolution of the set-up (shown with a dashed line inFigure 3b) and are in agreement with the 25 ps lifetime previ-ously reported for WSe2 bilayers.[44] Such a strong reduction ofthe PL lifetime may arise from two related effects. First, a similareffect has been observed in a gated bilayer WSe2,[45] where the ap-plication of a vertical electric field induces an increase of the inter-layer exciton lifetime, directly related to the enhanced spatial con-finement of the carriers in the adjacent layers. In our case, grad-ual tuning of the bandstructure towards that of a WSe2 bilayershould result in an increased spatial overlap of the electron andhole wavefunctions, leading to interlayer excitons with shorterlifetimes. On the other hand, as we discuss below, a gradual tran-sition to the indirect bandgap semiconductor with decreasing xshould lead to strong nonradiative decay,[46] as additionally evi-denced by the reduction of the overall PL emission in HBLs withsmall x (see Figure S11, Supporting Information).Further confirmation of this interpretation is obtained fromthe power dependence of the spectral position of the IX PL, whichcan be used to assess the efficiency of the exciton–exciton in-teraction between IXs. The IXs possess permanent dipole mo-ments, aligned along the direction normal to the plane of thedevice, resulting in enhanced repulsive dipolar exciton-excitoninteractions.[18] This gives rise to a blue-shift of the IX PL peakenergy at sufficiently high excitation density, i.e., for high IX den-sities. Above a certain power, both the blue-shift and the PL inten-sity saturate, due to the exciton-exciton annihilation processes.[47]Figure 3c shows experimentally measured blue-shift as a func-tion of the power of a continuous-wave laser in several HBLswith different x. We observe a maximum shift of 14 meV in aMoSe2/WSe2 structures at the excitation power of 80 μW in agree-ment with previously reported values.[18] The shift progressivelydecreases for smaller x and as the heterobilayer becomes moresimilar to a homobilayer, the blue-shift gradually disappears. Atthe same time, the power-dependences of PL intensities, show-ing saturation for high Mo concentrations, become nearly linearas x decreases (see Note S9, Supporting Information).We believe that these observations support the conclusions de-rived from the PL dynamics. For decreasing x, the electron andhole within the IX-like particle become less localized in the in-dividual layers. This will lead to a smaller dipole moment andthus weaker exciton-exciton interaction and a reduced blue-shift.At the same time, and possibly with a stronger influence on theobserved behavior, as the bandgap becomes indirect at small Moconcentrations, the fast non-radiative decay (e.g., caused by car-rier relaxation into the Q valley) prevents build-up of the exci-ton population thus suppressing the exciton–exciton interactionsand the corresponding blue-shift.3. DiscussionWe now further analyze the PL data and interpret the asymptoticbehavior of the IX energy as a function of x. The conduction- andvalence band energy offsets between the WSe2 and alloy layersforming a given HBL, ΔE1 and ΔE2, can be computed by sub-tracting the HBL bandgap from the intralayer bandgaps of theWSe2 and alloy layers, respectively (see the diagram in Figure 4a).To this end, we estimate the HBL bandgap as the IX energy, andthe intralayer gaps by the corresponding direct exciton energies,as obtained from PL measurements reported in Figure 2a,b. Inthis approximation, we are neglecting the exciton binding ener-gies and their x dependences,[43] thus incurring an error of theorder of tens of meV. The experimental x-dependent energy off-sets ΔE1 and ΔE2 are reported in Figure 4a, where two distincttrends can be observed for both curves, one for 0 ⩽ x ≲ 0.6 andanother for 0.6 ≲ x ⩽ 1.The band offset trends measured for 0.6 ≲ x ⩽ 1 can be ex-plained by simple interpolation of the conduction and valenceband edge energies of the alloy, assigning a linear trend to thelatter, and a quadratic trend to the former with the same bow-ing parameter measured for the direct A exciton in the alloy.[35]Such interpolation neglects the effects of hybridization betweenthe WSe2 and alloy layers, and assumes that, as is the case inMoSe2/WSe2 (x = 1),[13,40] the HBL bandgap remains at the Kpoint for all values of x. Full details of this approximation can befound in Note S10 (Supporting Information). The resulting inter-polations, shown with solid and dashed lines in Figure 4a, matchthe experimental trends for ΔE1 and ΔE2 only for 0.6 ≲ x ⩽ 1, in-dicating that interlayer hybridization in the HBL is weak for thisrange of Mo compositions, and that, indeed, the HBL bandgapremains at the K point. However, continuing the interpolationdown to x ≲ 0.6 we find a clear and dramatic deviation from theexperimental values, where the predicted offsets (dashed lines inFigure 4a) vanish for x = 0, while the experimental values (cir-cles in Figure 4a) converge at a saturation value around 200 meV.This deviation can be explained only if we consider major mod-ifications to the HBL bandstructure for 0 ⩽ x ≲ 0.6, such as atransition to an indirect bandgap for the HBL, caused by stronginterlayer hybridization at the Γ and Q points of the Brillouinzone.[48]To explore this possibility, we have formulated simple Hamil-tonians for interlayer hybridization of the WSe2 and alloy bandsin the HBL, at the K (conduction and valence), Γ (valence) andQ (conduction) points, with parameters based on density func-tional theory calculations extracted from Ref. [29]. It is worth-while mentioning that these models contain no free parameters.Further model details can be found in Note 10 (Supporting In-formation). Importantly, symmetry considerations[29] dictate thatthe model parameters differ for HBLs with interlayer angles closeto 0° and 60°. We have determined that the best match to the ex-perimental data is obtained assuming HBLs with 60° alignment(see Figure S18 and Note S10, Supporting Information), and limitour discussion to that case. The corresponding predictions for theband offsets ΔE1 and ΔE2, shown with red and black diamondsin Figure 4a, give an excellent quantitative match to the experi-mental data throughout the full range of compositions, and im-portantly with the saturation value of ≈200 meV at x = 0. Themodel shows that the HBL conduction band edge migrates fromthe K to the Q point for x < 0.65, whereas the HBL valence bandedge remains at the K point, as illustrated in Figure 4b, consistentwith recent theoretical reports for WSe2 bilayers.[29] This resultsin an indirect (K − Q) bandgap that changes the nature of the IX,thus shedding light on the change of trend of ΔE1 and ΔE2, theband offset saturation for x = 0, and the suppression of the IXenergy tuning with x for Mo concentrations below 0.65. More-over, the quantitative agreement between the model and exper-imental data strongly suggests that the samples studied are ap-proximately H-stacked HBLs, with an interlayer twist angle closeto 60°.Adv. Mater. 2024, 36, 2309644 2309644 (6 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.deΓ Q K Γ Q KWSe2HBLAlloy1 > x > 0.65 0.65 > x > 0IX1 IX1a bPLEnergyIX DXMoWSe2DXWSe2∆E2∆E1K-Q0.0 0.2 0.4 0.6 0.8 1.00.000.050.100.150.200.250.300.350.40BandoffsetsWSe2-MoWSe2(eV)Mo composition x in MoxW1-xSe2ΔE1 no hybrid.ΔE2 no hybrid.ΔE1 exp.ΔE2 exp.ΔE1 theoryΔE2 theoryFigure 4. Band offsets of the MoxW1 − xSe2/WSe2 HBLs. a) Band offsets of MoxW1 − xSe2/WSe2 HBLs as functions of Mo composition x in the alloylayers. The band offsets ΔE1 and ΔE2 are extracted as shown in the diagram in a from the experimentally measured PL peaks of IX in the HBLs and directexcitons DXMoWSe2in alloys and DXWSe2in WSe2 measured in isolated monolayers. Experimentally measured ΔE1 and ΔE2 are displayed as filled redand black circles, respectively. Red (black) solid and dashed lines show theoretical values for the conduction (valence) band offsets, obtained assuming adirect HBL bandgap at the K point, and neglecting interlayer band hybridization. The experimental energy offsets deviate significantly from the predictedtrend for x ≲ 0.6, suggesting strong interlayer band hybridization for that range of Mo concentrations. Empty diamonds show the theoretically predictedtrends for ΔE1 and ΔE2 when interlayer hybridization at the K, Q and Γ points of the Brillouin zone is considered, assuming an interlayer angle of 60°,showing excellent agreement with the experimental data for all x values. b) Sketch of the x-dependent HBL bandstructure evolution, according to theinterlayer band hybridization model. Dashed (solid) lines indicate the monolayer (HBL) band energies. Whereas for x > 0.65 the HBL remains direct dueto weak hybridization at the K point, strong hybridization of conduction states shifts the conduction band edge to the Q point for x < 0.65, resulting inan indirect K − Q bandgap, and a finite momentum for the IX.We now briefly comment on the simultaneous observation ofIX1 peak and a high energy PL feature ≈1.55 eV (similar to IX2in bilayer WSe2) in the HBL with x = 0.21. While IX1 PL orig-inates from the K − Q transition, as suggested above, the fol-lowing options for the origin of the 1.55 eV feature may be pro-posed. As can be deduced from the broad spectral features inMo0.21W0.79Se2/WSe2 alloy mono- and bilayers, this material ishighly disordered. This may lead to occurrence of W-rich clus-ters, which will locally behave as WSe2 bilayers, thus giving riseto PL at the IX2 energy. Another explanation, assuming a moreeven distribution of Mo in the alloy is related to PL emission in-volving Γ − Q transition, expected around 50 meV higher thanK − Q, and activated in this alloy either due to the increased dis-order or a relatively high hole concentration.4. ConclusionsIn summary, we have demonstrated significant tuning of IX en-ergy in MoxW1 − xSe2/WSe2 and MoxW1 − xSe2/MoSe2 alloy het-erostructures by changing the Mo composition x. We use PL mea-surements at 10 K, where we observe a shift of IX PL energy by130 meV in MoxW1 − xSe2/WSe2 as a function of x, as well asan unusual asymptotic dependence of IX PL energy approachingthe homobilayer configuration. We show that this behavior stemsfrom strong hybridization between conduction states of the WSe2and alloyed layers for x < 0.65, when the interlayer conductionband offset falls below ≈250 meV, leading to a K − Q indirectbandgap for the heterostructure, and thus changing the nature ofthe IX. We probed the effects of such strong bandstructure mod-ifications on IX also by means of time-resolved PL experimentsand by measuring PL power dependences, supporting our con-clusion about the transition to an indirect bandgap in the HBLswith x< 0.65. We also find similar effects in MoxW1 − xSe2/MoSe2HBLs. As background information, we also extract detailed en-ergy dependences of A- and B- excitons, A* trions and IX inmonolayer and bilayer MoxW1 − xSe2 as a function of x.This work demonstrates the potential of adopting TMD al-loys in vdW heterobilayers to achieve continuous bandstructuretuning, and fine band hybridization engineering. Tuning the A-exciton energy and band-edge offsets using alloying provides anadditional probing approach for lattice reconstruction phenom-ena, currently actively being discussed in theory and observed inmicroscopy and optical spectroscopy experiments.[27–30]5. Experimental SectionFabrication of alloy HSs: High-quality fully encapsulated HBL sampleswere fabricated using PMMA-assisted dry-peel transfer. To minimize con-tamination, heterostructures were fabricated using a remotely controlledmicromanipulation setup placed inside an argon chamber with <0.1 ppmO2 and H2O. The bulk crystals were mechanically exfoliated onto a 90 nmlayer of PMMA coated on a silicon wafer. Monolayers were then identifiedvia optical microscopy, as well as through luminescence imaging in theAdv. Mater. 2024, 36, 2309644 2309644 (7 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.dedark-field configuration. Crystals that had adjacent straight edges at 0°,60°, or 120° to one another (indicating one of the crystallographic axes)were then selected and picked up onto an hBN film (less than around 10nm thickness) held by a PMMA membrane. During the transfer of the sec-ond TMD layer the edges were aligned to within 0.5° of the desired angleand finally transferred onto another hBN film (less or around 20 nm thick-ness) exfoliated onto an oxidized silicon wafer (70 nm SiO2) to achieve fullencapsulation. To prevent spontaneous rotation of the TMD layers and de-terioration of MoSe2 crystalline quality, exposure of the heterostructuresto temperatures greater than 70°C was avoided. See further details of thefabrication procedure in Note S1 (Supporting Information).Optical Measurements: The photoluminescence images of the hetero-bilayer samples were acquired using a modified bright-field microscope(LV150N, Nikon) equipped with a colour camera (DS-Vi1, Nikon). Thenear-infrared emission from the white-light source was blocked with a 550-nm short-pass filter (FESH0550, Thorlabs), and a 600-nm long-pass filter(FELH0600, Thorlabs) was used to isolate the photoluminescence signalfrom the sample.Spectrally-resolved photoluminescence and reflectance con-trast measurements were performed using a custom-built micro-photoluminescence setup. For photoluminescence, the excitation lightcentred at 2.33 eV was generated by a diode-pumped solid-state laser(CW532-050, Roithner), whereas for reflectance contrast a stabilizedtungsten-halogen white-light source (SLS201L, Thorlabs) was used. Theexcitation light was focused onto the sample using a 50x objective lens (MPlan Apo 50X, Mitutoyo). The photoluminescence and reflectance con-trast signals collected in the backwards direction were detected by a 0.5-mspectrometer (HRS-500, Princeton Instruments) with a nitrogen-cooledcharge-coupled device camera (PyLoN:100BR, Princeton Instruments).The photoluminescence signal was isolated using a 550-nm short-passfilter (FELH0550, Thorlabs). The reflectance contrast spectra were derivedby comparing the spectra of white light reflected from the sample and thesubstrate as RC(𝜆) = (R(𝜆) - R0(𝜆))/(R0(𝜆)), where R (R0) is the intensityof light reflected by the sample (substrate). The room-temperature mea-surements were performed in ambient conditions. The low-temperaturemeasurements were carried out using a continuous-flow liquid heliumcryostat, in which the sample was placed on a cold finger with a basetemperature of 10 K.To acquire the PL decay of the IX in the entire set of samples, the emit-ted photons were detected with an avalanche diode photodetector (APD)(ID100-MMF50), with a timing resolution of ∼40 ps, and a photon count-ing card (SPC-130). A 638 nm pulsed diode laser (PicoQuant LDH) wasused as excitation source, with 80 MHz repetition rate, which resulted ina instrument response function (IRF) with ≈150 ps FWHM.Supporting InformationSupporting Information is available from the Wiley Online Library or fromthe author.AcknowledgementsA.C., L.S., R.P., K.E., and A.I.T. acknowledge financial support of the Eu-ropean Commission H2020-MSCA-ITN project under grant agreements676108. A.G., C.L., D.J.G., E.A., and A.T. acknowledge financial supportof the European Graphene Flagship Projects under grant agreements785219 and 881603 and EPSRC grants EP/V006975/1, EP/V026496/1,EP/V034804/1, and EP/S030751/1. V.F. and K.E. acknowledge financialsupport of the European Graphene Flagship Project under grant agree-ment 881603. A.G. acknowledges support by the European Union projectENOSIS H2020-MSCA-IF-2020-101029644. K.W. and T.T. acknowledgesupport from the JSPS KAKENHI (Grant Numbers 20H00354, 21H05233,and 23H02052) and World Premier International Research Centre Initia-tive (WPI), MEXT, Japan. D.A.R.T. acknowledges funding from PAPIIT-DGAPA-UNAM grant IA106523. L.S. acknowledges support through aHumboldt Research Fellowship from the Alexander von Humboldt Foun-dation. K.S.N. acknowledges support from the Ministry of Education, Sin-gapore (Research Centre of Excellence award to the Institution for Func-tional Intelligent Materials, I-FIM, project No EDUNC-33-18-279-V12) andfrom the Royal Society (UK, grant number RSRP\R\190000). V.F. acknowl-edges EPSRC grants EP/V007033/1 and EP/S030719/1.Conflict of InterestThe authors declare no conflict of interest.Author ContributionsA.C., R.P., L.H., A.K., and C.L. fabricated heterostructure samples. K.W.and T.T. synthesized the high quality hBN. A.C., A.G., C.L., D.J.G., L.S.,and E.A. carried out optical spectroscopy measurements. A.C., A.G., andC.L. analyzed the data with contribution from D.J.G., L.S., E.A., A.I.T. andD.A.R.T. D.A.R.T. and V.F. developed theory. A.G., C.L., A.I.T., and D.A.R.T.wrote the manuscript with contribution from all co-authors. A.I.T., K.E.,and K.S.N. managed various experimental aspects of the project. A.I.T.conceived and supervised the project.Data Availability StatementThe data that support the findings of this study are available from thecorresponding author upon reasonable request.Keywords2D materials, heterobilayers, interlayer excitons, semiconductors, transi-tion metal dichalcogenides, van der Waals heterostructuresReceived: September 18, 2023Revised: December 20, 2023Published online: February 13, 2024[1] A. K. Geim, I. V. Grigorieva, Nature 2013, 499, 419.[2] K. Novoselov, A. Mishchenko, A. Carvalho, A. C. Neto, Science 2016,353, aac9439.[3] Y. Tang, J. Gu, S. Liu, K. Watanabe, T. Taniguchi, J. Hone, K. F. Mak, J.Shan, Nat. Nanotechnol. 2021, 16, 52.[4] J. Kang, S. Tongay, J. Zhou, J. Li, J. Wu, Appl. Phys. Lett. 2013, 102, 22.[5] C. Gong, H. Zhang, W. Wang, L. Colombo, R. M. Wallace, K. Cho,Appl. Phys. Lett. 2013, 103, 1.[6] D. Huang, J. Choi, C.-K. Shih, X. Li, Nat. Nanotechnol. 2022, 17, 227.[7] D. Schmitt, J. P. Bange, W. Bennecke, A. AlMutairi, G. Meneghini, K.Watanabe, T. Taniguchi, D. Steil, D. R. Luke, R. T. Weitz, S. Steil, G.S. Matthijs Jansen, S. Brem, E. Malic, S. Hofmann, M. Reutzel, S.Mathias, Nature 2022, 608, 499.[8] T. Li, S. Jiang, L. Li, Y. Zhang, K. Kang, J. Zhu, K. Watanabe, T.Taniguchi, D. Chowdhury, L. Fu, J. Shan, K. F. Mak, Nature 2021, 597,350.[9] E. M. Alexeev, D. A. Ruiz-Tijerina, M. Danovich, M. J. Hamer, D. J.Terry, P. K. Nayak, S. Ahn, S. Pak, J. Lee, J. I. Sohn, M. R. Molas,M. Koperski, K. Watanabe, T. Taniguchi, K. S. Novoselov, R. V.Gorbachev, H. S. Shin, V. I. Fal’ko, A. I. Tartakovskii, Nature 2019,567, 81.[10] N. P. Wilson, W. Yao, J. Shan, X. Xu, Nature 2021, 599, 383.[11] K. Tran, G. Moody, F. Wu, X. Lu, J. Choi, K. Kim, A. Rai, D. A. Sanchez,J. Quan, A. Singh, J. Embley, A. Zepeda, M. Campbell, T. Autry, T.Taniguchi, K. Watanabe, N. Lu, S. K. Banerjee, K. L. Silverman, S. Kim,E. Tutuc, L. Yang, A. H. MacDonald, X. Li, Nature 2019, 567, 1.Adv. Mater. 2024, 36, 2309644 2309644 (8 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.dewww.advancedsciencenews.com www.advmat.de[12] A. J. Jones, R. Muzzio, S. Pakdel, D. Biswas, D. Curcio, N. Lanatà, P.Hofmann, K. M. McCreary, B. T. Jonker, K. Watanabe, T. Taniguchi, S.Singh, R. J. Koch, C. Jozwiak, E. Rotenberg, A. Bostwick, J. A. Miwa, J.Katoch, S. Ulstrup, 2D Mater. 2021, 9, 015032.[13] N. R. Wilson, P. V. Nguyen, K. Seyler, P. Rivera, A. J. Marsden, Z. P. L.Laker, G. C. Constantinescu, V. Kandyba, A. Barinov, N. D. M. Hine,X. Xu, D. H. Cobden, Sci. Adv. 2017, 3, 1.[14] H. Baek, M. Brotons-Gisbert, Z. X. Koong, A. Campbell, M.Rambach, K. Watanabe, T. Taniguchi, B. D. Gerardot, arXiv preprintarXiv:2001.04305 2020.[15] Y. Tang, L. Li, T. Li, Y. Xu, S. Liu, K. Barmak, K. Watanabe, T. Taniguchi,A. H. MacDonald, J. Shan, K. F. Mak, Nature 2020, 579, 353.[16] Y. Xu, K. Kang, K. Watanabe, T. Taniguchi, K. F. Mak, J. Shan, Nat.Nanotechnol. 2022, 17, 934.[17] Y. Shimazaki, I. Schwartz, K. Watanabe, T. Taniguchi, M. Kroner, A.Imamoğlu, Nature 2020, 580, 472.[18] P. Rivera, J. R. Schaibley, A. M. Jones, J. S. Ross, S. Wu, G. Aivazian,P. Klement, K. Seyler, G. Clark, N. J. Ghimire, J. Yan, D. G. Mandrus,W. Yao, X. Xu, Nat. Commun. 2015, 6, 1.[19] P. Rivera, H. Yu, K. L. Seyler, N. P. Wilson, W. Yao, X. Xu, Nat. Nan-otechnol. 2018, 13, 1.[20] Y. Jiang, S. Chen, W. Zheng, B. Zheng, A. Pan, Light: Sci. Appl. 2021,10, 72.[21] S. Adachi, Properties of semiconductor alloys: group-IV, III-V and II-VIsemiconductors, vol. 28, John Wiley & Sons, 2009.[22] L. Xie, Nanoscale 2015, 7, 18392.[23] G. Wang, C. Robert, A. Suslu, B. Chen, S. Yang, S. Alamdari, I. C. G.,T. Amand, X. Marie, S. Tongay, B. Urbaszek, Nat. Commun. 2015, 6,1.[24] J. Ye, B. Niu, Y. Li, T. Li, X. Zhang, Appl. Phys. Lett. 2017, 111, 152106.[25] L. Li, W. Zheng, C. Ma, H. Zhao, F. Jiang, Y. Ouyang, B. Zheng, X. Fu,P. Fan, M. Zheng, Y. Li, Y. Xiao, W. Cao, Y. Jiang, X. Zhu, X. Zhuang,A. Pan, Nano Lett. 2020, 20, 3361.[26] Y. Zi, C. Li, C. Niu, F. Wang, J.-H. Cho, Y. Jia, J. Phys.: Condens.Matter2019, 31, 435503.[27] A. Weston, Y. Zou, V. Enaldiev, A. Summerfield, N. Clark, V. Zólyomi,A. Graham, C. Yelgel, S. Magorrian, M. Zhou, J. Zultak, D. Hopkinson,A. Barinov, T. H. Bointon, A. Kretinin, N. R. Wilson, P. H. Beton, V. I.Fal’ko, S. J. Haigh, R. Gorbachev, Nat. Nanotechnol. 2020, 15, 592.[28] V. V. Enaldiev, V. Zólyomi, C. Yelgel, S. J. Magorrian, V. I. Fal’ko, Phys.Rev. Lett. 2020, 124, 206101.[29] S. Magorrian, V. Enaldiev, V. Zólyomi, F. Ferreira, V. I. Fal’ko, D. A.Ruiz-Tijerina, Phys. Rev. B 2021, 104, 125440.[30] S. Zhao, Z. Li, X. Huang, A. Rupp, J. Göser, I. A. Vovk, S. Y. Kruchinin,K. Watanabe, T. Taniguchi, I. Bilgin, A. S. Baimuratov, A. Högele, Nat.Nanotechnol. 2023, 18, 572.[31] E. M. Alexeev, A. Catanzaro, O. V. Skrypka, P. K. Nayak, S. Ahn, S. Pak,J. Lee, J. I. Sohn, K. S. Novoselov, H. S. Shin, A. I. Tartakovskii, NanoLett. 2017, 17, 5342.[32] X. Hong, J. Kim, S.-F. Shi, Y. Zhang, C. Jin, Y. Sun, S. Tongay, J. Wu, Y.Zhang, F. Wang, Nat. Nanotechnol. 2014, 9, 1.[33] P. Rivera, J. R. Schaibley, A. M. Jones, J. S. Ross, S. Wu, G. Aivazian,P. Klement, K. Seyler, G. Clark, N. J. Ghimire, J. Yan, D. G. Mandrus,W. Yao, X. Xu, Nat. Commun. 2015, 6.[34] J. Kopaczek, T. Wozniak, M. Tamulewicz-Szwajkowska, S. J. Zelewski,J. Serafinczuk, P. Scharoch, R. Kudrawiec, ACS omega 2021, 6,19893.[35] A. R. Denton, N. W. Ashcroft, Phys. Rev. A 1991, 43, 3161.[36] S. Tongay, D. S. Narang, J. Kang, W. Fan, C. Ko, A. V. Luce, K. X. Wang,J. Suh, K. D. Patel, V. M. Pathak, J. Li, J. Wu, Appl. Phys. Lett. 2014, 104,1.[37] M. Zhang, J. Wu, Y. Zhu, D. O. Dumcenco, J. Hong, N. Mao, S. Deng,Y. Chen, Y. Yang, C. Jin, S. H. Chaki, Y.-S. Huang, J. Zhang, L. Xie, ACSNano 2014, 8, 7130.[38] M. R. Molas, K. Nogajewski, A. O. Slobodeniuk, J. Binder, M. Bartos,M. Potemski, Nanoscale 2017, 9, 13128.[39] B. Miller, A. Steinhoff, B. Pano, J. Klein, F. Jahnke, A. Holleitner, U.Wurstbauer, Nano Lett. 2017, 17, 5229.[40] E. Barré, O. Karni, E. Liu, A. L. O’Beirne, X. Chen, H. B. Ribeiro,L. Yu, B. Kim, K. Watanabe, T. Taniguchi, K. Barmak, C. H. Lui, S.Refaely-Abramson, F. H. Da Jornada, T. F. Heinz, Science 2022, 376,406.[41] J. Lindlau, M. Selig, A. Neumann, L. Colombier, J. Förste, V. Funk, M.Förg, J. Kim, G. Berghäuser, T. Taniguchi, K. Watanabe, F. Wang, E.Malic, A. Högele, Nat. Commun. 2018, 9, 1.[42] J. Holler, M. Selig, M. Kempf, J. Zipfel, P. Nagler, M. Katzer, F. Katsch,M. V. Ballottin, A. A. Mitioglu, A. Chernikov, P. C. M. Christianen, C.Schüller, A. Knorr, T. Korn, Phys. Rev. B 2022, 105, 085303.[43] S. Ovesen, S. Brem, C. Linderälv, M. Kuisma, T. Korn, P. Erhart, M.Selig, E. Malic, Commun. Phys. 2019, 2, 23.[44] G. Wang, X. Marie, L. Bouet, M. Vidal, A. Balocchi, T. Amand, D.Lagarde, B. Urbaszek, Appl. Phys. Lett. 2014, 105, 1.[45] Z. Wang, Y.-H. Chiu, K. Honz, K. F. Mak, J. Shan, Nano Lett. 2018, 18,137.[46] G. Wang, X. Marie, L. Bouet, M. Vidal, A. Balocchi, T. Amand, D.Lagarde, B. Urbaszek, Appl. Phys. Lett. 2014, 105, 182105.[47] D. Sun, Y. Rao, G. A. Reider, G. Chen, Y. You, L. Bre?zin, A. R.Harutyunyan, T. F. Heinz, Nano Lett. 2014, 14, 5625.[48] V. Kravtsov, A. D. Liubomirov, R. V. Cherbunin, A. Catanzaro, A.Genco, D. Gillard, E. M. Alexeev, T. Ivanova, E. Khestanova, I. A.Shelykh, A. I. Tartakovskii, M. S. Skolnick, D. N. Krizhanovskii1, I. V.Iorsh, 2D Mater. 2021, 8, 025011.Adv. Mater. 2024, 36, 2309644 2309644 (9 of 9) © 2024 The Authors. Advanced Materials published by Wiley-VCH GmbH 15214095, 2024, 19, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adma.202309644 by National Institute For, Wiley Online Library on [10/06/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.advmat.de Resonant Band Hybridization in Alloyed Transition Metal Dichalcogenide Heterobilayers 1. Introduction 2. Results 3. Discussion 4. Conclusions 5. Experimental Section Supporting Information Acknowledgements Conflict of Interest Author Contributions Data Availability Statement Keywords