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Zhijie Li, Farsane Tabataba-Vakili, Shen Zhao, Anna Rupp, Ismail Bilgin, Ziria Herdegen, Benjamin März, [Kenji Watanabe](https://orcid.org/0000-0003-3701-8119), [Takashi Taniguchi](https://orcid.org/0000-0002-1467-3105), Gabriel Ravanhani Schleder, Anvar S. Baimuratov, Efthimios Kaxiras, Knut Müller-Caspary, Alexander Högele

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[Lattice Reconstruction in MoSe<sub>2</sub>–WSe<sub>2</sub> Heterobilayers Synthesized by Chemical Vapor Deposition](https://mdr.nims.go.jp/datasets/e1c3c413-7c8e-46da-9e50-b76474eaf668)

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Lattice Reconstruction in MoSe2–WSe2 Heterobilayers Synthesized by Chemical Vapor DepositionLattice Reconstruction in MoSe2−WSe2 Heterobilayers Synthesizedby Chemical Vapor DepositionZhijie Li,○ Farsane Tabataba-Vakili,*,○ Shen Zhao,○ Anna Rupp, Ismail Bilgin, Ziria Herdegen,Benjamin März, Kenji Watanabe, Takashi Taniguchi, Gabriel Ravanhani Schleder, Anvar S. Baimuratov,Efthimios Kaxiras, Knut Müller-Caspary, and Alexander Högele*Cite This: Nano Lett. 2023, 23, 4160−4166 Read OnlineACCESS Metrics & More Article Recommendations *sı Supporting InformationABSTRACT: Vertical van der Waals heterostructures of semiconduct-ing transition metal dichalcogenides realize moire ́ systems with richcorrelated electron phases and moire ́ exciton phenomena. For materialcombinations with small lattice mismatch and twist angles as inMoSe2−WSe2, however, lattice reconstruction eliminates the canonicalmoire ́ pattern and instead gives rise to arrays of periodicallyreconstructed nanoscale domains and mesoscopically extended areasof one atomic registry. Here, we elucidate the role of atomicreconstruction in MoSe2−WSe2 heterostructures synthesized bychemical vapor deposition. With complementary imaging down tothe atomic scale, simulations, and optical spectroscopy methods, weidentify the coexistence of moire-́type cores and extended moire-́freeregions in heterostacks with parallel and antiparallel alignment. Ourwork highlights the potential of chemical vapor deposition for applications requiring laterally extended heterosystems of one atomicregistry or exciton-confining heterostack arrays.KEYWORDS: two-dimensional semiconductors, MoSe2−WSe2, heterostructures, chemical vapor deposition, lattice reconstruction,atomic registries, interlayer excitonsVertical heterostructures of transition metal dichalcogenidesemiconductors manifest in two contrasting regimes. Onthe one hand, exfoliation-stacked heterobilayers with finitelattice mismatch or twist angle give rise to periodic two-dimensional (2D) moire ́ patterns, which in turn result in flatmoire ́ minibands of charge carriers with rich phenomena ofcorrelated Hubbard model physics.1−6 Moire ́ potentials alsoprofoundly affect strongly bound electron−hole pairs in theform of intralayer7,8 and interlayer9−12 excitons formed byCoulomb correlations within or across individual layers. Thisscenario is contrasted by moire-́free heterobilayers on the otherhand, obtained from chemical vapor deposition (CVD)synthesis,13−15 where the absence of lateral moire ́ potentialsis signified by one atomic registry extending laterally over largesample areas15 with simple photoluminescence (PL) spectra13or enhanced diffusion of interlayer excitons.14 Heterostructuresystems with diffusive interlayer excitons represent an idealmaterial platform for integrated dipolar exciton circuits,16 asdemonstrated recently in exfoliation-stacked heterostructureswith an additional interfacial layer of hexagonal boron nitride(hBN), which mitigates the exciton-confining moire ́ poten-tial.17,18 Even more promising are CVD-synthesized hetero-bilayers free of moire ́ effects, featuring enhanced diffusivity ofdipolar interlayer excitons,14 unaffected by diffusion-inhibitingmoire ́ confinement.14,19,20 Such moire-́free heterostructures arenot only ideal for integrated exciton circuits with externalcontrol by electrostatic gates,21,22 they could also enabledeterministically imprinting arbitrary, tunable potential land-scapes via patterned gate-electrodes,23,24 or dielectric super-lattices.25Moire-́free domains on micrometer length scales also emergein heterostructures with small lattice mismatch and marginaltwist subject to mesoscopic lattice reconstruction, where thedriving mechanism behind atom rearrangement into energeti-cally favorable registries is provided by the competitionbetween intralayer strain and interlayer adhesion energy,26−28yielding mesoscopic 2D domains of only one registry inMoSe2−WSe2 stamping-assembled heterostacks.29 For prac-tical applications, however, such nondeterministic fabricationmethods with resulting spatial inhomogeneities in morphologyReceived: December 29, 2022Revised: March 7, 2023Published: May 4, 2023Letterpubs.acs.org/NanoLett© 2023 The Authors. Published byAmerican Chemical Society4160https://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−4166Downloaded via 220.150.145.156 on May 27, 2023 at 01:37:24 (UTC).See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Zhijie+Li"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Farsane+Tabataba-Vakili"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Shen+Zhao"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Anna+Rupp"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ismail+Bilgin"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ziria+Herdegen"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Benjamin+Ma%CC%88rz"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Benjamin+Ma%CC%88rz"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Kenji+Watanabe"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takashi+Taniguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Gabriel+Ravanhani+Schleder"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Anvar+S.+Baimuratov"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Efthimios+Kaxiras"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Efthimios+Kaxiras"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Knut+Mu%CC%88ller-Caspary"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Alexander+Ho%CC%88gele"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/showCitFormats?doi=10.1021/acs.nanolett.2c05094&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?goto=articleMetrics&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?goto=recommendations&?ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?goto=supporting-info&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=tgr1&ref=pdfhttps://pubs.acs.org/toc/nalefd/23/10?ref=pdfhttps://pubs.acs.org/toc/nalefd/23/10?ref=pdfhttps://pubs.acs.org/toc/nalefd/23/10?ref=pdfhttps://pubs.acs.org/toc/nalefd/23/10?ref=pdfpubs.acs.org/NanoLett?ref=pdfhttps://pubs.acs.org?ref=pdfhttps://pubs.acs.org?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://pubs.acs.org/NanoLett?ref=pdfhttps://pubs.acs.org/NanoLett?ref=pdfhttps://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/https://acsopenscience.org/open-access/licensing-options/and optical properties29 limit the required uniformity andscalability, rendering CVD-based approaches to large-areamoire-́free systems a promising alternative.In this work, we present an elaborate study of CVD-synthesized vertical MoSe2−WSe2 heterobilayers with evidencefor extended reconstruction into domains of one atomicregistry, enclosing a central region of periodically reconstructednanoscale domains.26,27,29 Our studies cover both high-symmetry stacking configurations with 0° (R-type) and 180°(H-type) twist angle, and employ complementary imaging andoptical spectroscopy methods to identify the diversity in localconfigurations of the reconstructed crystal lattice and therespective signatures of exciton transitions. Our work high-lights the potential of CVD synthesis for obtaining bothextended moire-́free domains and exciton-confining arrays ofperiodically reconstructed moire ́ regions, realizing the limits ofdipolar excitons with and without a spatially varying potentiallandscape.Our samples with MoSe2−WSe2 heterobilayers consist oflarge monolayers of MoSe2 with monolayers of WSe2 on top,both synthesized by CVD in a two-step growth (see Sections 1and 2 in the Supporting Information for details). Figure 1adepicts an optical micrograph of an as-grown heterobilayer,showing the formation of both H- and R-type stackings. Weexamined another heterobilayer sample synthesized in thesame growth run by scanning electron microscopy (SEM),with representative images shown in Figure 1b,c. The imagesof H- and R-type samples were recorded with secondaryelectron imaging with material- and stacking-sensitive con-trast29−31 (see Section 3 in the Supporting Information fordetails), clearly discerning a small triangle in the center of theheterostack.Three high-symmetry atomic registries are distinguished inH- and R-type heterostructures, namely Hhh, HhM, HhX and Rhh,RhM, RhX, with M, X, and h referring to the transition metal,chalcogen, and center of the hexagon, and the superscript andsubscript to the MoSe2 and WSe2 layer, respectively (note thatthe nomenclature is chosen to be consistent with previouswork29,32,33). In Figure 1d,e, we show density functional theory(DFT) calculations of the generalized stacking fault energy(GSFE)26 for the different atomic registries with local extremaat the three high-symmetry stackings (see Section 4 in theSupporting Information for details) indicated by the respectivetop-view schematics. Minima in GSFE correspond to theFigure 1. MoSe2−WSe2 heterobilayers: sample structure of CVD-synthesized H- and R-type stacks and theory of stacking fault energy. (a) Opticalmicrograph of an as-grown heterobilayer consisting of a large triangular MoSe2 monolayer with an outer edge of monolayer WSe2 and triangles ofmonolayer WSe2 on top with 0° (R-type) and 180° (H-type) twist. The white circles indicate the H- and R-type flakes studied by opticalspectroscopy. (b, c) SEM images (recorded with secondary electron imaging and shown with inverted black-and-white contrast) of tworepresentative H- and R-type heterobilayers synthesized in the same growth. (d, e) DFT calculations of the generalized stacking fault energy for thedifferent stackings in H- and R-type heterostructures, respectively, including top views of the three high-symmetry atomic registries with W (blue,top layer), Mo (red, bottom layer), and Se (gray) atoms. Inset in part e: Zoom to the minima at RhM and RhX stackings.Figure 2. HAADF-STEM imaging and simulations. (a) Top row: Measurement (left) and simulation (right) of MoSe2 monolayer. Bottom rows:Simulations of the three high-symmetry stackings in H-type (left column) and R-type (right column) heterostacks. (b−d) HAADF-STEM imagesof heterobilayers in Hhh, RhM, and RhX stacking, respectively. Insets show images averaged over ten unit cells.Nano Letters pubs.acs.org/NanoLett Letterhttps://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−41664161https://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.2c05094/suppl_file/nl2c05094_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.2c05094/suppl_file/nl2c05094_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.2c05094/suppl_file/nl2c05094_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig2&ref=pdfpubs.acs.org/NanoLett?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asenergetically most favorable stackings that dominate thereconstruction.28 In the H-type case shown in Figure 1d, theHhh atomic registry is by far the energetically most favorable,consistent with prior work.26,28,29 In contrast, in the R-typecase (Figure 1e) both RhM and RhX stackings are close to theoptimal energy, with RhM being slightly more favorable (inset ofFigure 1e). This implies close competition between the tworegistries, with a higher likelihood of RhM to form extendeddomains.Our study of individual heteroflakes with aberration-corrected high-resolution high-angle annular dark-field scan-ning transmission electron microscopy (HAADF-STEM) (seeSection 5 in the Supporting Information for details) confirmsthe exclusive dominance of the Hhh atomic registry in H-typeheterostacks, as well as the reconstruction of R-type stacks intoRhM and RhX registries. To begin with, we establish theorientation of the crystallographic axes in the heterobilayersusing the surrounding MoSe2 monolayer, with measurement(left) and simulation (right) of the hexagonal lattice shown inthe top row of Figure 2a. For this orientation, the bottom rowsin Figure 2a show simulations of the three possible high-symmetry stackings in H- and R-type, which compete forenergy minimization in reconstruction. In stacks of H-type, ourexperiments with results as in Figure 2b identify the Hhhstacking only, in agreement with the theoretical predictionabove. In R-type heterostacks, on the other hand, we observeextended areas of RhM registry in some flakes (as in Figure 2c),while other flakes exhibit extended areas of RhX stacking (as inFigure 2d). Given the close similarity of the two registryconfigurations with regard to optimal energy, it is plausible thatsome R-type flakes reconstruct into RhM while others take onthe RhX stacking and that their distribution is stochastic on theflake-to-flake case.To study the optical properties of CVD-synthesized H- andR-type crystals, we encapsulated the sample shown in Figure 1ain hBN (see Section 6 in the Supporting Information fordetails) and performed cryogenic confocal PL and differentialreflectance (DR) spectroscopy. Each atomic registry uniquelydetermines the combination of transition energies,29,32,34optical selection rules,32,34,35 and oscillator strengths36,37 ofinterlayer excitons and thus provides means for spectroscopiccharacterization. For our sample, the maps of maximuminterlayer exciton PL intensity in H- and R-type hetero-structures are shown in Figure 3a,b with dashed linesindicating the heterostack boundaries. The H-type sampleshows extended areas of bright interlayer exciton PL (as on thespot marked by the brown cross in Figure 3a) and a darkregion near the center (blue cross in Figure 3a). The R-typesample features similar local variations in the PL map, yet withnearly 2 orders of magnitude lower intensity.The low intensity of R-type as compared to H-type stacks issurprising, as reconstructed mechanically stacked samplessupport the opposite trend.29 This observation suggests thatdomains of RhM registry with relatively dark interlayer excitonsdominate CVD-grown R-type heterostacks. In the areas ofmaximum PL intensity marked by brown crosses in Figure 3, aand b, both H- and R-stacks feature simple spectra withdominant peaks at 1.40 and 1.45 eV in Figure 3, c and d,respectively. In the H-stack, the PL peak at 1.40 eV with apositive degree of circular polarization Pc (shown in thebottom panel of Figure 3c) corresponds to the triplet interlayerexciton transition in extended Hhh domains of reconstructedmechanically stacked samples,29 and is accompanied by a weakhot-luminescence singlet at 1.42 eV with negative Pc.13,29,38,39The main peak in the R-type stack, on the other hand, is blue-shifted by 120 meV from its counterpart observed onreconstructed RhX domains of mechanically stacked hetero-structures at 1.33 eV29 and exhibits zero Pc in Figure 3d. Thisfinding, combined with the PL energy position and reducedrelative brightness, corroborates our assumption about the RhMcharacter of interlayer exciton states with z-polarizedFigure 3. CVD-heterobilayers in cryogenic spectroscopy. (a, b) Mapsof interlayer PL maximum intensity (dashed lines show flakeboundaries from optical images, dotted lines delimit the centraltriangles, and solid lines indicate from top left to bottom rightintensity profiles in Figure 5c,d). (c, d) Top panel: Interlayer excitonPL spectra recorded with linearly polarized excitation and circularlypolarized detection at positions shown by the brown and blue crossesin parts a and b (the spectra below 1.37 eV in part d are multiplied by10 for better visibility), with atomic registries assigned to thecorresponding transitions. Bottom panel: Degree of circular polar-ization Pc measured at the position of the brown cross in parts a andb. (e, f) Differential reflectance (DR) spectra corresponding to areasindicated by brown and blue crosses in parts a and b. All data wererecorded at 4 K, with 100 μW excitation in PL spectroscopy.Nano Letters pubs.acs.org/NanoLett Letterhttps://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−41664162https://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.2c05094/suppl_file/nl2c05094_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.2c05094/suppl_file/nl2c05094_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig3&ref=pdfpubs.acs.org/NanoLett?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-astransitions.29,35,37 Finally, we observe that areas of maximumPL intensity exhibit simple resonances of intralayer exciton inthe DR spectra of H- and R-type stacks (shown in Figure 3e,ffor positions indicated by brown crosses in Figure 3a,b) as ahallmark of extended areas of one dominant atomic registry.29We also point out the absence of trion-related resonances inthe DR spectra of both stacks as a signature of low residualdoping, which we also confirmed with PL spectroscopy awayfrom heterostacks on monolayer MoSe2 (data not shown).In the central areas of H- and R-type stacks marked by bluecrosses in the areas of dotted triangles in Figure 3a,b andspectra in Figure 3c,d, we observe reduced intensity of themain PL peaks and an additional spectral feature around 1.35eV with negative Pc (not shown) in the R-type case. The latteris a feature of RhX atomic registry,29 which coexists with RhM inthe core of the heterostack. This conclusion, substantiated bythe observation of doublets in the DR spectra of Figure 3e,fnear the intralayer exciton resonance of MoSe2 at 1.62 eV,identifies the central triangles as arrays of reconstructed quasizero-dimensional (0D) domains,29 which can form as nano-scale hexagons of Hhh registry in H-type and in triangular tilingof RhX and RhM domains in R-type stacks.28 Although the spatialresolution of the SEM in secondary-electron imaging isinsufficient to detect the actual tiling geometry, the differencein the contrast between the outer regions of both types ofheterostacks and their triangular cores in Figure 1b,c providescompelling support for the assignment of the triangular centersto reconstructed 0D arrays.To elaborate on the nature of interlayer excitons in extendedRhM domains not reported previously for MoSe2−WSe2heterostacks, we performed angle-resolved PL measurements.Using momentum-space imaging40 with the 2D k-space profileshown in Figure 4a for the PL from a bright H-type area, wefirst confirm the in-plane character of the optical dipoleorientation for Hhh interlayer excitons for reference. TheirGaussian emission profile, with highest intensity at zero in-plane k-vector in the linecut at kx = 0 (bottom panel of Figure4a) is contrasted by the R-type case in Figure 4b: The PLemission in the energy range 1.43−1.46 eV assigned to RhMatomic registry is nearly zero at small k-vectors and increaseswith increasing k as a hallmark of out-of-plane dipole momentorientation.41 With the detection angle of 54° of our objective,we observe the PL from out-of-plane oriented interlayerexcitons in RhM atomic registry, which are dark at normalincidence and exhibit z-polarized emission according to dipolarselection rules.35To complete the correspondence between the signatures ofinterlayer excitons in stamping-assembled29 and CVD-synthe-sized heterostacks studied here, we discuss the results ofmagneto-luminescence experiments in Faraday configurationshown in Figure 4c,d for H- and R-type stacks, respectively. Infinite magnetic fields, the interlayer triplet and singlet excitonsin domains of Hhh atomic registry feature circularly polarizedtransitions, with linear valley Zeeman splitting given by Δz = E+− E− = gμBB (with magnetic field B, Bohr magneton μB,exciton Lande ́ factor g, and E± referring to the dispersionbranch measured under σ+ and σ− detection). The triplet andsinglet transitions differ characteristically in both sign andmagnitude of their exciton Lande ́ g-factors, determined fromthe slopes of simultaneous linear fits to the data in Figure 4c as−17.0 ± 0.4 and +11.5 ± 0.3, respectively, in agreement withDFT calculations29,33,37 and previous experiments.9,29,39,42−45In the R-type case, the magnetic field dependence of the z-po l a r i z ed RhM i n t e r l a y e r e x c i t on i s g i v en by= ± +±E E z0122 2 with zero-field exciton energy withoutexchange interaction E0 and exchange splitting δ.46 In Figure4d, both dispersion branches are observed in both circularpolarizations, and respecting the sign convention we thusobtain from the fit to the data with δ = 0.1 meV the absolutevalue of the exciton Lande ́ factor as |g| = 6.5. The g-factor is inquantitative agreement with DFT, predicting a value of 6.3.29,37In the central triangle (data not shown), we determine for RhXan interlayer exciton g-factor of +7.0 ± 0.2 in agreement withprevious experiments and theory.9,29,33,39Last, we note that in between extended bright areas in thePL maps of Figure 3a,b, we observed reduced PL intensities,which we ascribe to grain boundaries separating reconstructed2D domains. Figure 5a shows PL and Pc spectra at such a darkposition in the H-type stack with Hhh triplet and singlet excitoncharacteristics and slightly reduced Pc as compared to a brightspot with data in Figure 3c. The variations in the PL intensityof Hhh interlayer excitons in Figure 5c is consistent with localreduction in emission (dip around 4 μm with width given bythe optical spot) in between two bright areas separated by agrain boundary. At the corresponding positions with reducedPL in the R-type stack, we observe additional contributionsFigure 4. Momentum-space and magneto-optical characteristics ofinterlayer exciton luminescence. (a, b) Top panels: Momentum-spacemaps of interlayer exciton PL in H- and R-type samples, respectively(tunable long- and short-pass filters were used to limit the detectionin part b to the energy range of 1.43−1.46 eV). Bottom panels:Emission profiles at kx = 0. (c, d) Magneto-dispersion recorded underlinearly polarized excitation and circularly polarized detection, withLande ́ g-factors extracted from fits to the data. Inset in part d: Zoomto the dispersion around zero field, with emphasis on the dark excitonexchange splitting δ of 0.1 meV. All measurements were performed at100 μW excitation power and 4 K.Nano Letters pubs.acs.org/NanoLett Letterhttps://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−41664163https://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig4&ref=pdfpubs.acs.org/NanoLett?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asfrom RhX and Rhh atomic registries with spectra in Figure 5b andnegative and positive Pc, respectively.29,35 The spatial intensityprofiles of RhM and RhX interlayer exciton PL in Figure 5d areanticorrelated, identifying grain boundaries as mutuallyexclusive areas of competing registries with additionalcontribution from Rhh interlayer excitons via hot lumines-cence.29The comparison of spectral characteristics of CVD-grownMoSe2−WSe2 heterostacks with our prior work on mechan-ically stacked samples29 yields qualitatively equivalent resultsanticipated from general theoretical considerations. In H-typestacks, we found domains of Hhh atomic registry to dominateextended areas of heterostacks, encompassing a triangular coreof 0D domains. In R-type stacks, RhM and RhX domains coexist intriangular cores of CVD-heteroflakes and compete for mutuallyexclusive reconstruction in the surrounding domains. In R-typestacks with extended domains of RhM atomic registries, weidentify the spectral signatures of interlayer excitons notreported previously from mechanically stacked samples. Weanticipate that in CVD-grown heterostacks reconstructiontakes place during high-temperature synthesis and thus isrobust against postprocessing steps of sample transfer orannealing at much lower temperatures. With extendedreconstructed 2D domains and 0D arrays in their innercores, CVD-grown MoSe2−WSe2 heterostacks realize areas ofboth moire-́free and moire-́like systems. While the latter aretechnologically viable as quantum dot arrays of exciton-confining potentials on the nanoscale32,34 and the former fordipolar exciton circuitry and extrinsic gate-modulation ofpotential landscapes,16,21,22 grain boundaries between domainsof different atomic registries could host excitons withtopological protection.47■ ASSOCIATED CONTENT*sı Supporting InformationThe Supporting Information is available free of charge athttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094.Synthesis of MoSe2−WSe2 heterobilayers, samplefabrication, SEM imaging, theoretical modeling, STEMimaging, and optical spectroscopy (PDF)■ AUTHOR INFORMATIONCorresponding AuthorsFarsane Tabataba-Vakili − Fakultät für Physik, MunichQuantum Center, and Center for NanoScience (CeNS),Ludwig-Maximilians-Universität München, 80539 München,Germany; Munich Center for Quantum Science andTechnology (MCQST), 80799 München, Germany;orcid.org/0000-0001-5911-7594; Email: f.tabataba@lmu.deAlexander Högele − Fakultät für Physik, Munich QuantumCenter, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München,Germany; Munich Center for Quantum Science andTechnology (MCQST), 80799 München, Germany;orcid.org/0000-0002-0178-9117;Email: alexander.hoegele@lmu.deAuthorsZhijie Li − Fakultät für Physik, Munich Quantum Center, andCenter for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, GermanyShen Zhao − Fakultät für Physik, Munich Quantum Center,and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, GermanyAnna Rupp − Fakultät für Physik, Munich Quantum Center,and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, GermanyIsmail Bilgin − Fakultät für Physik, Munich Quantum Center,and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München, GermanyZiria Herdegen − Department of Chemistry and Center forNanoScience, Ludwig-Maximilians-Universität München,81377 München, GermanyBenjamin März − Department of Chemistry and Center forNanoScience, Ludwig-Maximilians-Universität München,81377 München, Germany; orcid.org/0000-0003-1628-9868Kenji Watanabe − Research Center for Functional Materials,National Institute for Materials Science, Tsukuba 305-0044,Japan; orcid.org/0000-0003-3701-8119Takashi Taniguchi − International Center for MaterialsNanoarchitectonics, National Institute for Materials Science,Tsukuba 305-0044, Japan; orcid.org/0000-0002-1467-3105Gabriel Ravanhani Schleder − John A. Paulson School ofEngineering and Applied Sciences, Harvard University,Cambridge, Massachusetts 02138, United StatesAnvar S. Baimuratov − Fakultät für Physik, Munich QuantumCenter, and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, 80539 München,GermanyEfthimios Kaxiras − John A. Paulson School of Engineeringand Applied Sciences, Harvard University, Cambridge,Massachusetts 02138, United States; Department of Physics,Figure 5. Spectral characteristics of grain boundaries. (a, b) Top andbottom panels: Interlayer exciton PL spectra and degree of circularpolarization Pc at grain boundaries in H- and R-type samples,respectively. (c, d) Spatial variations in the interlayer exciton PL ofdifferent atomic registries upon lateral transition from one bright spotto another indicated in the maps of Figure 3. All measurements wereperformed at 100 μW excitation power and 4 K.Nano Letters pubs.acs.org/NanoLett Letterhttps://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−41664164https://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?goto=supporting-infohttps://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.2c05094/suppl_file/nl2c05094_si_001.pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Farsane+Tabataba-Vakili"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0001-5911-7594https://orcid.org/0000-0001-5911-7594mailto:f.tabataba@lmu.demailto:f.tabataba@lmu.dehttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Alexander+Ho%CC%88gele"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-0178-9117https://orcid.org/0000-0002-0178-9117mailto:alexander.hoegele@lmu.dehttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Zhijie+Li"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Shen+Zhao"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Anna+Rupp"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ismail+Bilgin"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ziria+Herdegen"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Benjamin+Ma%CC%88rz"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0003-1628-9868https://orcid.org/0000-0003-1628-9868https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Kenji+Watanabe"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0003-3701-8119https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takashi+Taniguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-1467-3105https://orcid.org/0000-0002-1467-3105https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Gabriel+Ravanhani+Schleder"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Anvar+S.+Baimuratov"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Efthimios+Kaxiras"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?fig=fig5&ref=pdfpubs.acs.org/NanoLett?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asHarvard University, Cambridge, Massachusetts 02138,United StatesKnut Müller-Caspary − Department of Chemistry and Centerfor NanoScience, Ludwig-Maximilians-Universität München,81377 München, GermanyComplete contact information is available at:https://pubs.acs.org/10.1021/acs.nanolett.2c05094Author Contributions○Z. L., F. T.-V. and S. Z. contributed equally to this work.NotesThe authors declare no competing financial interest.■ ACKNOWLEDGMENTSThis research was funded by the European Research Council(ERC) under Grant Agreement No. 772195 as well as theDeutsche Forschungsgemeinschaft (DFG, German ResearchFoundation) within the Priority Programme SPP 2244 2DMPand Germany’s Excellence Strategy under Grant No. EXC-2111-390814868 and EXC-2089-390776260. Z.L. was sup-ported by the China Scholarship Council (CSC), grant No.201808140196. F.T.-V. acknowledges funding from theMunich Center for Quantum Science and Technology andthe European Union’s Framework Programme for Researchand Innovation Horizon Europe under the Marie Skłodowska-Curie Actions Grant Agreement No. 101058981. S.Z. and I.B.acknowledge funding from the Alexander von HumboldtFoundation, and A.S.B. acknowledges funding from theEuropean Union’s Framework Programme for Research andInnovation Horizon 2020 (2014−2020) under the MarieSkłodowska-Curie Grant Agreement No. 754388 (LMUR-esearchFellows) and from LMUexcellent, funded by theFederal Ministry of Education and Research (BMBF) andthe Free State of Bavaria under the Excellence Strategy of theGerman Federal Government and the Länder. A.R., K.M.-C.and A.H. acknowledge funding by the Bavarian HightechAgenda within the Munich Quantum Valley doctoral fellow-ship program and the EQAP project. G.R.S. acknowledgesfunding from the Army Research Office under CooperativeAgreement No. W911NF-21-2-0147. E.K. acknowledgesfunding from the STC Center for Integrated QuantumMaterials, NSF Grant No. DMR-1231319, NSF DMREFAward No. 1922172, and the Army Research Office underCooperative Agreement No. W911NF-21-2-0147. K.W. andT.T. acknowledge support from JSPS KAKENHI (grant No.19H05790, 20H00354 and 21H05233).■ REFERENCES(1) Wu, F.; Lovorn, T.; Tutuc, E.; MacDonald, A. H. Hubbardmodel physics in transition metal dichalcogenide moire ́ bands. Phys.Rev. Lett. 2018, 121, 026402.(2) Tang, Y.; Li, L.; Li, T.; Xu, Y.; Liu, S.; Barmak, K.; Watanabe, K.;Taniguchi, T.; MacDonald, A. H.; Shan, J.; Mak, K. F. Simulation ofHubbard model physics in WSe2/WS2 moire ́ superlattices. Nature2020, 579, 353.(3) Shimazaki, Y.; Schwartz, I.; Watanabe, K.; Taniguchi, T.; Kroner,M.; Imamoğlu, A. Strongly correlated electrons and hybrid excitons ina moire ́ heterostructure. Nature 2020, 580, 472.(4) Regan, E. C.; Wang, D.; Jin, C.; Bakti Utama, M. I.; Gao, B.;Wei, X.; Zhao, S.; Zhao, W.; Zhang, Z.; Yumigeta, K.; Blei, M.;Carlström, J. D.; Watanabe, K.; Taniguchi, T.; Tongay, S.; Crommie,M.; Zettl, A.; Wang, F. Mott and generalized Wigner crystal states inWSe2/WS2 moire ́ superlattices. Nature 2020, 579, 359.(5) Xu, Y.; Liu, S.; Rhodes, D. A.; Watanabe, K.; Taniguchi, T.;Hone, J.; Elser, V.; Mak, K. F.; Shan, J. Correlated insulating states atfractional fillings of moire ́ superlattices. Nature 2020, 587, 214.(6) Tang, Y.; Gu, J.; Liu, S.; Watanabe, K.; Taniguchi, T.; Hone, J.C.; Mak, K. F.; Shan, J. Dielectric catastrophe at the Mott and Wignertransitions in a moire ́ superlattice. Nat. Commun. 2022, 13, 4271.(7) Zhang, N.; Surrente, A.; Baranowski, M.; Maude, D. K.; Gant, P.;Castellanos-Gomez, A.; Plochocka, P. Moire ́ intralayer excitons in aMoSe2/MoS2 heterostructure. Nano Lett. 2018, 18, 7651.(8) Naik, M. H.; Regan, E. C.; Zhang, Z.; Chan, Y.-H.; Li, Z.; Wang,D.; Yoon, Y.; Ong, C. S.; Zhao, W.; Zhao, S.; Utama, M. I. B.; Gao, B.;Wei, X.; Sayyad, M.; Yumigeta, K.; Watanabe, K.; Taniguchi, T.;Tongay, S.; da Jornada, F. H.; Wang, F.; Louie, S. G. Intralayercharge-transfer moire ́ excitons in van der Waals superlattices. Nature2022, 609, 52.(9) Seyler, K. L.; Rivera, P.; Yu, H.; Wilson, N. P.; Ray, E. L.;Mandrus, D. G.; Yan, J.; Yao, W.; Xu, X. Signatures of moire-́trappedvalley excitons in MoSe2/WSe2 heterobilayers. Nature 2019, 567, 66.(10) Tran, K.; Moody, G.; Wu, F.; Lu, X.; Choi, J.; Kim, K.; Rai, A.;Sanchez, D. A.; Quan, J.; Singh, A.; Embley, J.; Zepeda, A.; Campbell,M.; Autry, T.; Taniguchi, T.; Watanabe, K.; Lu, N.; Banerjee, S. K.;Silverman, K. L.; Kim, S.; Tutuc, E.; Yang, L.; MacDonald, A. H.; Li,X. Evidence for moire ́ excitons in van der Waals heterostructures.Nature 2019, 567, 71.(11) Jin, C.; Regan, E. C.; Yan, A.; Iqbal Bakti Utama, M.; Wang, D.;Zhao, S.; Qin, Y.; Yang, S.; Zheng, Z.; Shi, S.; Watanabe, K.;Taniguchi, T.; Tongay, S.; Zettl, A.; Wang, F. Observation of moire ́excitons in WSe2/WS2 heterostructure superlattices. Nature 2019,567, 76.(12) Alexeev, E. M.; Ruiz-Tijerina, D. A.; Danovich, M.; Hamer, M.J.; Terry, D. J.; Nayak, P. K.; Ahn, S.; Pak, S.; Lee, J.; Sohn, J. I.;Molas, M. R.; Koperski, M.; Watanabe, K.; Taniguchi, T.; Novoselov,K. S.; Gorbachev, R. V.; Shin, H. S.; Fal’ko, V. I.; Tartakovskii, A. I.Resonantly hybridized excitons in moire ́ superlattices in van derWaals heterostructures. Nature 2019, 567, 81.(13) Hsu, W.-T.; Lu, L.-S.; Wu, P.-H.; Lee, M.-H.; Chen, P.-J.; Wu,P.-Y.; Chou, Y.-C.; Jeng, H.-T.; Li, L.-J.; Chu, M.-W.; Chang, W.-H.Negative circular polarization emissions from WSe2/MoSe2 commen-surate heterobilayers. Nat. Commun. 2018, 9, 1356.(14) Choi, J.; Hsu, W.-T.; Lu, L.-S.; Sun, L.; Cheng, H.-Y.; Lee, M.-H.; Quan, J.; Tran, K.; Wang, C.-Y.; Staab, M.; Jones, K.; Taniguchi,T.; Watanabe, K.; Chu, M.-W.; Gwo, S.; Kim, S.; Shih, C.-K.; Li, X.;Chang, W.-H. Moire ́ potential impedes interlayer exciton diffusion invan der Waals heterostructures. Sci. Adv. 2020, 6, No. eaba8866.(15) Xia, J.; Yan, J.; Wang, Z.; He, Y.; Gong, Y.; Chen, W.; Sum, T.C.; Liu, Z.; Ajayan, P. M.; Shen, Z. Strong coupling and pressureengineering in WSe2-MoSe2 heterobilayers. Nat. Phys. 2021, 17, 92.(16) Butov, L. V. Excitonic devices, Superlattices and Microstructures2017, 108, 2.(17) Sun, Z.; Ciarrocchi, A.; Tagarelli, F.; Gonzalez Marin, J. F.;Watanabe, K.; Taniguchi, T.; Kis, A. Excitonic transport driven byrepulsive dipolar interaction in a van der Waals heterostructure. Nat.Photonics 2022, 16, 79.(18) Shanks, D. N.; Mahdikhanysarvejahany, F.; Stanfill, T. G.;Koehler, M. R.; Mandrus, D. G.; Taniguchi, T.; Watanabe, K.; LeRoy,B. J.; Schaibley, J. R. Interlayer exciton diode and transistor. NanoLett. 2022, 22, 6599.(19) Yuan, L.; Zheng, B.; Kunstmann, J.; Brumme, T.; Kuc, A. B.;Ma, C.; Deng, S.; Blach, D.; Pan, A.; Huang, L. Twist-angle-dependent interlayer exciton diffusion in WS2-WSe2 heterobilayers.Nat. Mater. 2020, 19, 617.(20) Wang, J.; Shi, Q.; Shih, E.-M.; Zhou, L.; Wu, W.; Bai, Y.;Rhodes, D.; Barmak, K.; Hone, J.; Dean, C. R.; Zhu, X.-Y. DiffusivityReveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2Heterobilayers. Phys. Rev. Lett. 2021, 126, 106804.(21) Jiang, Y.; Chen, S.; Zheng, W.; Zheng, B.; Pan, A. Interlayerexciton formation, relaxation, and transport in TMD van der Waalsheterostructures. Light Sci. Appl. 2021, 10, 72.Nano Letters pubs.acs.org/NanoLett Letterhttps://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−41664165https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Knut+Mu%CC%88ller-Caspary"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/doi/10.1021/acs.nanolett.2c05094?ref=pdfhttps://doi.org/10.1103/PhysRevLett.121.026402https://doi.org/10.1103/PhysRevLett.121.026402https://doi.org/10.1038/s41586-020-2085-3https://doi.org/10.1038/s41586-020-2085-3https://doi.org/10.1038/s41586-020-2191-2https://doi.org/10.1038/s41586-020-2191-2https://doi.org/10.1038/s41586-020-2092-4https://doi.org/10.1038/s41586-020-2092-4https://doi.org/10.1038/s41586-020-2868-6https://doi.org/10.1038/s41586-020-2868-6https://doi.org/10.1038/s41467-022-32037-1https://doi.org/10.1038/s41467-022-32037-1https://doi.org/10.1021/acs.nanolett.8b03266?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.nanolett.8b03266?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1038/s41586-022-04991-9https://doi.org/10.1038/s41586-022-04991-9https://doi.org/10.1038/s41586-019-0957-1https://doi.org/10.1038/s41586-019-0957-1https://doi.org/10.1038/s41586-019-0975-zhttps://doi.org/10.1038/s41586-019-0976-yhttps://doi.org/10.1038/s41586-019-0976-yhttps://doi.org/10.1038/s41586-019-0986-9https://doi.org/10.1038/s41586-019-0986-9https://doi.org/10.1038/s41467-018-03869-7https://doi.org/10.1038/s41467-018-03869-7https://doi.org/10.1126/sciadv.aba8866https://doi.org/10.1126/sciadv.aba8866https://doi.org/10.1038/s41567-020-1005-7https://doi.org/10.1038/s41567-020-1005-7https://doi.org/10.1038/s41566-021-00908-6https://doi.org/10.1038/s41566-021-00908-6https://doi.org/10.1021/acs.nanolett.2c01905?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1038/s41563-020-0670-3https://doi.org/10.1038/s41563-020-0670-3https://doi.org/10.1103/PhysRevLett.126.106804https://doi.org/10.1103/PhysRevLett.126.106804https://doi.org/10.1103/PhysRevLett.126.106804https://doi.org/10.1038/s41377-021-00500-1https://doi.org/10.1038/s41377-021-00500-1https://doi.org/10.1038/s41377-021-00500-1pubs.acs.org/NanoLett?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as(22) Ciarrocchi, A.; Tagarelli, F.; Avsar, A.; Kis, A. Excitonic deviceswith van der Waals heterostructures: valleytronics meets twistronics.Nat. Rev. Mater. 2022, 7, 449.(23) Shanks, D. N.; Mahdikhanysarvejahany, F.; Muccianti, C.;Alfrey, A.; Koehler, M. R.; Mandrus, D. G.; Taniguchi, T.; Watanabe,K.; Yu, H.; LeRoy, B. J.; Schaibley, J. R. Nanoscale trapping ofinterlayer excitons in a 2D semiconductor heterostructure. Nano Lett.2021, 21, 5641.(24) Shanks, D. N.; Mahdikhanysarvejahany, F.; Koehler, M. R.;Mandrus, D. G.; Taniguchi, T.; Watanabe, K.; LeRoy, B. J.; Schaibley,J. R. Single exciton trapping in an electrostatically defined 2Dsemiconductor quantum dot. Phys. Rev. B 2022, 106, L201401.(25) Shi, L.-k.; Ma, J.; Song, J. C. Gate-tunable flat bands in van derWaals patterned dielectric superlattices. 2D Mater. 2020, 7, 015028.(26) Carr, S.; Massatt, D.; Torrisi, S. B.; Cazeaux, P.; Luskin, M.;Kaxiras, E. Relaxation and domain formation in incommensurate two-dimensional heterostructures. Phys. Rev. B 2018, 98, 224102.(27) Enaldiev, V.; Zólyomi, V.; Yelgel, C.; Magorrian, S.; Fal’ko, V.Stacking domains and dislocation networks in marginally twistedbilayers of transition metal dichalcogenides. Phys. Rev. Lett. 2020, 124,206101.(28) Rosenberger, M. R.; Chuang, H.-J.; Phillips, M.; Oleshko, V. P.;McCreary, K. M.; Sivaram, S. V.; Hellberg, C. S.; Jonker, B. T. Twistangle-dependent atomic reconstruction and moire ́ patterns intransition metal dichalcogenide heterostructures. ACS Nano 2020,14, 4550.(29) Zhao, S.; Li, Z.; Huang, X.; Rupp, A.; Göser, J., Vovk, I. A.;Kruchinin, S. Y.; Watanabe, K.; Taniguchi, T.; Bilgin, I.; Baimuratov,A. S.; Högele, A. Excitons in mesoscopically reconstructed moire ́heterostructures. arXiv preprint 2022; arXiv:2202.11139;https://arxiv.org/abs/2202.11139 (accessed March 3, 2022).(30) Ashida, K.; Kajino, T.; Kutsuma, Y.; Ohtani, N.; Kaneko, T.Crystallographic orientation dependence of SEM contrast revealed bySiC polytypes. J. Vac. Sci. Technol. B 2015, 33, 04E104.(31) Andersen, T. I.; Scuri, G.; Sushko, A.; De Greve, K.; Sung, J.;Zhou, Y.; Wild, D. S.; Gelly, R. J.; Heo, H.; Bérubé, D.; Joe, A. Y.;Jauregui, L. A.; Watanabe, K.; Taniguchi, T.; Kim, P.; Park, H.; Lukin,M. D. Excitons in a reconstructed moire ́ potential in twisted WSe2/WSe2 homobilayers. Nat. Mater. 2021, 20, 480.(32) Yu, H.; Liu, G.-B.; Tang, J.; Xu, X.; Yao, W. Moire ́ excitons:From programmable quantum emitter arrays to spin-orbit−coupledartificial lattices. Sci. Adv. 2017, 3, No. e1701696.(33) Woźniak, T.; Faria Junior, P. E.; Seifert, G.; Chaves, A.;Kunstmann, J. Exciton g-factors of van der Waals heterostructuresfrom first principles calculations. Phys. Rev. B 2020, 101, 235408.(34) Wu, F.; Lovorn, T.; MacDonald, A. Theory of opticalabsorption by interlayer excitons in transition metal dichalcogenideheterobilayers. Phys. Rev. B 2018, 97, 035306.(35) Förg, M.; Colombier, L.; Patel, R. K.; Lindlau, J.; Mohite, A. D.;Yamaguchi, H.; Glazov, M. M.; Hunger, D.; Högele, A. Cavity-controlof interlayer excitons in van der Waals heterostructures. Nat. Commun.2019, 10, 3697.(36) Gillen, R.; Maultzsch, J. Interlayer excitons in MoSe2/WSe2heterostructures from first principles. Phys. Rev. B 2018, 97, 165306.(37) Förg, M.; Baimuratov, A. S.; Kruchinin, S. Y.; Vovk, I. A.;Scherzer, J.; Förste, J.; Funk, V.; Watanabe, K.; Taniguchi, T.; Högele,A. Moire ́ excitons in MoSe2-WSe2 heterobilayers and heterotrilayers.Nat. Commun. 2021, 12, 1656.(38) Hanbicki, A. T.; Chuang, H.-J.; Rosenberger, M. R.; Hellberg,C. S.; Sivaram, S. V.; McCreary, K. M.; Mazin, I. I.; Jonker, B. T.Double indirect interlayer exciton in a MoSe2/WSe2 van der Waalsheterostructure. ACS Nano 2018, 12, 4719.(39) Joe, A. Y.; Jauregui, L. A.; Pistunova, K.; Mier Valdivia, A. M.;Lu, Z.; Wild, D. S.; Scuri, G.; De Greve, K.; Gelly, R. J.; Zhou, Y.;Sung, J.; Sushko, A.; Taniguchi, T.; Watanabe, K.; Smirnov, D.; Lukin,M. D.; Park, H.; Kim, P. Electrically controlled emission from singletand triplet exciton species in atomically thin light-emitting diodes.Phys. Rev. B 2021, 103, L161411.(40) Dominguez, D.; Alharbi, N.; Alhusain, M.; Bernussi, A. A.;Peralta, L. G. d. Fourier plane imaging microscopy. J. Appl. Phys.2014, 116, 103102.(41) Li, Z.; Wang, T.; Lu, Z.; Khatoniar, M.; Lian, Z.; Meng, Y.; Blei,M.; Taniguchi, T.; Watanabe, K.; McGill, S. A.; Tongay, S.; Menon,V. M.; Smirnov, D.; Shi, S.-F. Direct observation of gate-tunable darktrions in monolayer WSe2. Nano Lett. 2019, 19, 6886.(42) Nagler, P.; Ballottin, M. V.; Mitioglu, A. A.; Mooshammer, F.;Paradiso, N.; Strunk, C.; Huber, R.; Chernikov, A.; Christianen, P. C.M.; Schüller, C.; Korn, T. Giant magnetic splitting inducing near-unity valley polarization in van der Waals heterostructures. Nat.Commun. 2017, 8, 1551.(43) Wang, T.; Miao, S.; Li, Z.; Meng, Y.; Lu, Z.; Lian, Z.; Blei, M.;Taniguchi, T.; Watanabe, K.; Tongay, S.; Smirnov, D.; Shi, S.-F. GiantValley-Zeeman Splitting from Spin-Singlet and Spin-Triplet InterlayerExcitons in WSe2/MoSe2 Heterostructure. Nano Lett. 2020, 20, 694.(44) Delhomme, A.; Vaclavkova, D.; Slobodeniuk, A.; Orlita, M.;Potemski, M.; Basko, D. M.; Watanabe, K.; Taniguchi, T.; Mauro, D.;Barreteau, C.; Giannini, E.; Morpurgo, A. F.; Ubrig, N.; Faugeras, C.Flipping exciton angular momentum with chiral phonons in MoSe2/WSe2 heterobilayers. 2D Mater. 2020, 7, 041002.(45) Brotons-Gisbert, M.; Baek, H.; Molina-Sánchez, A.; Campbell,A.; Scerri, E.; White, D.; Watanabe, K.; Taniguchi, T.; Bonato, C.;Gerardot, B. D. Spin−layer locking of interlayer excitons trapped inmoire ́ potentials. Nat. Mater. 2020, 19, 630.(46) Robert, C.; Amand, T.; Cadiz, F.; Lagarde, D.; Courtade, E.;Manca, M.; Taniguchi, T.; Watanabe, K.; Urbaszek, B.; Marie, X. Finestructure and lifetime of dark excitons in transition metaldichalcogenide monolayers. Phys. Rev. B 2017, 96, 155423.(47) Chaves, A.; Covaci, L.; Peeters, F. M.; Milosěvic,́ M. V.Topologically protected moire ́ exciton at a twist-boundary in a vander Waals heterostructure. 2D Mater. 2022, 9, 025012.Nano Letters pubs.acs.org/NanoLett Letterhttps://doi.org/10.1021/acs.nanolett.2c05094Nano Lett. 2023, 23, 4160−41664166https://doi.org/10.1038/s41578-021-00408-7https://doi.org/10.1038/s41578-021-00408-7https://doi.org/10.1021/acs.nanolett.1c01215?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.nanolett.1c01215?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1103/PhysRevB.106.L201401https://doi.org/10.1103/PhysRevB.106.L201401https://doi.org/10.1088/2053-1583/ab59a8https://doi.org/10.1088/2053-1583/ab59a8https://doi.org/10.1103/PhysRevB.98.224102https://doi.org/10.1103/PhysRevB.98.224102https://doi.org/10.1103/PhysRevLett.124.206101https://doi.org/10.1103/PhysRevLett.124.206101https://doi.org/10.1021/acsnano.0c00088?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.0c00088?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.0c00088?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://arxiv.org/abs/2202.11139https://arxiv.org/abs/2202.11139https://doi.org/10.1116/1.4927136https://doi.org/10.1116/1.4927136https://doi.org/10.1038/s41563-020-00873-5https://doi.org/10.1038/s41563-020-00873-5https://doi.org/10.1126/sciadv.1701696https://doi.org/10.1126/sciadv.1701696https://doi.org/10.1126/sciadv.1701696https://doi.org/10.1103/PhysRevB.101.235408https://doi.org/10.1103/PhysRevB.101.235408https://doi.org/10.1103/PhysRevB.97.035306https://doi.org/10.1103/PhysRevB.97.035306https://doi.org/10.1103/PhysRevB.97.035306https://doi.org/10.1038/s41467-019-11620-zhttps://doi.org/10.1038/s41467-019-11620-zhttps://doi.org/10.1103/PhysRevB.97.165306https://doi.org/10.1103/PhysRevB.97.165306https://doi.org/10.1038/s41467-021-21822-zhttps://doi.org/10.1021/acsnano.8b01369?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.8b01369?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1103/PhysRevB.103.L161411https://doi.org/10.1103/PhysRevB.103.L161411https://doi.org/10.1063/1.4895157https://doi.org/10.1021/acs.nanolett.9b02132?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.nanolett.9b02132?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1038/s41467-017-01748-1https://doi.org/10.1038/s41467-017-01748-1https://doi.org/10.1021/acs.nanolett.9b04528?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.nanolett.9b04528?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.nanolett.9b04528?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1088/2053-1583/aba567https://doi.org/10.1088/2053-1583/aba567https://doi.org/10.1038/s41563-020-0687-7https://doi.org/10.1038/s41563-020-0687-7https://doi.org/10.1103/PhysRevB.96.155423https://doi.org/10.1103/PhysRevB.96.155423https://doi.org/10.1103/PhysRevB.96.155423https://doi.org/10.1088/2053-1583/ac529dhttps://doi.org/10.1088/2053-1583/ac529dpubs.acs.org/NanoLett?ref=pdfhttps://doi.org/10.1021/acs.nanolett.2c05094?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as