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Pushkar Dasika, Patrick Hays, Suchithra Puliyassery, [Kenji Watanabe](https://orcid.org/0000-0003-3701-8119), [Takashi Taniguchi](https://orcid.org/0000-0002-1467-3105), Seth Ariel Tongay, Kausik Majumdar

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This document is the Accepted Manuscript version of a Published Article that appeared in final form in ACS Nano, copyright © 2025 American Chemical Society. To access the final published article, see https://doi.org/10.1021/acsnano.4c14983.[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

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[Hot Electron Engineering in Layered Heterojunctions for Efficient Infrared Detection](https://mdr.nims.go.jp/datasets/2c3ef0e5-9403-4d19-811e-50adf4ed69f1)

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Hot electron engineering in layeredheterojunction for efficient infrared detectionPushkar Dasika1, Patrick Hays2, Suchithra Puliyassery1, Kenji Watanabe3,Takashi Taniguchi4, Seth Ariel Tongay2 and Kausik Majumdar1∗1Department of Electrical Communication Engineering,Indian Institute of Science, Bangalore 560012, India2Materials Science and Engineering, School for Engineering of Matter,Transport and Energy,Arizona State University, Tempe, Arizona 85287, USA3Research Center for Electronic and Optical Materials,National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan4Research Center for Materials Nanoarchitectonics,National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, JapanCorresponding author∗E-mail: kausikm@iisc.ac.in1AbstractAlthough infrared detection is of high technological and strategic impor-tance, the narrow-bandgap materials used for infrared detection often sufferfrom poor air stability and pose environmental hazards. Hot electron-baseddetectors avoid such issues by using conventional wide bandgap semiconduc-tors and exploiting intra-band transition. However, hot electron infrareddetectors usually suffer from poor quantum efficiency. By photo-excitingMoS2 conduction electrons over a thin barrier layer, here we show thata reversal of the role of the emitter and collector results in a > 1000-foldenhancement in the photoresponse compared with conventional metal/2Dsemiconductor Schottky diode. We reveal that electron-electron scatteringplays a key role in the device performance, which can be effectively tunedby a gate voltage. The photodetector exhibits a nearly flat response upto a measurement wavelength of 1800 nm with a responsivity of 42 mA/W(@1550 nm) at room temperature. We demonstrate an operating frequencyof 30 kHz @1550nm excitation (100 kHz @633 nm). The detector chip is in-tegrated with post-processing electronics in a printed circuit board, makingit readily usable for system-level applications - a demonstration of hetero-geneous integration of 2D materials with conventional electronics.Keywords: Hot electrons, Infrared Photodetector, van der Waals heterostructure, Broad-band, Circuit integration2Infrared (IR) photodetection is of great importance for a wide variety of technologies.Photodetection in the wavelength range of the C band (1528–1561 nm) and the L band(1561–1620 nm) is crucial for low-loss optical communication systems.1,2 IR photodetec-tors find extensive applications in imaging,3 spectroscopy,4 night vision cameras,5 and non-invasive biomedical applications.6 Conventional inter-band photodetectors, where incidentphotons excite valence band electrons to the conduction band, are limited by their bandgapto detect long wavelength (lower energy) IR radiation. Thus, one must use narrow bandgapsemiconductors to detect infrared photons. Unfortunately, these low-bandgap materials usu-ally suffer from problems with stability, complex growth techniques, challenges in integrationinto standard fabrication flows, and often possess environment-safety-and-health (ESH) re-lated concerns.7–9To this end, two-dimensional layered materials have garnered significant attention inthe last decade owing to their extraordinary electrical, mechanical and optical proper-ties.10–15 Gate-tunability and ease of formation of atomically smooth heterojunctions, with alarge library of materials, made them highly attractive for sensitive photodetection applica-tions,16–20 including the IR regime.21–28 Unfortunately, there are similar concerns, as statedabove, regarding the narrow bandgap layered materials as well.27–29Using widely available, air-stable, large bandgap materials for IR detection alleviatesmost of the above problems. However, the use of such materials would require a funda-mentally different photodetection mechanism. A well-known mechanism is the intrabandphoto-excitation of carriers and subsequent collection of the hot carriers through a hetero-junction,30,31 also called internal photoemission. Schottky diodes,30,32–34 and more recentlyGraphene / 3D semiconductor Schottky junctions35–38 and metal/2D Semiconductor Schot-tky junctions39–43 have been explored for this purpose.Unfortunately, due to the reasons stated below, for these Schottky junction devices, andmore so for those that use 2D layered materials, the achieved internal quantum efficiency ispoor, plaguing the achievable photodetection efficiency and hence limiting their widespread3applications. This work aims to propose and demonstrate a different class of intraband IRdetector that intrinsically addresses this issue.Internal quantum efficiency bottleneck: A typical Schottky photodiode utilizes theheterojunction between a metal and a bulk semiconductor as shown in Figure 1a. When themetal absorbs photons with energy above the Schottky barrier height (SBH), the hot elec-trons overcome the barrier and get injected into the semiconductor.44,45 The built-in electricfield in the semiconductor, due to band bending, pulls the photoinduced electrons away fromthe junction (Figure 1b). The primary bottleneck in the internal quantum efficiency arisesfrom the large free electron density in the metal, which causes rapid carrier relaxation due toultrafast electron-electron (e-e) scattering (shown by red dashed arrow in Figure 1b) . Thisresults in a small fraction of the generated hot electrons to overcome the Schottky barrier.E C CELTECE(a) (c) (f)(b) (d) (e)E C(g)ExyyBBCCECyx yyEnergyFigure 1: Internal quantum efficiency in hot electron photodetectors and proposedsolution: (a) A typical Schottky diode-based photodetector with metal emitter (E) andbulk semiconducting collector (C). (b) Band diagram of (a) along the dashed line. (c) A2D hot-electron photodetector without any barrier layer. (d-e) Band diagrams of (c) alongthe horizontal black dashed line (d) and along the vertical magenta dashed line (e). Thetransfer length (LT ) region is indicated by the dashed box. (f) The proposed 2D hot-electronphotodetector with a barrier layer (shown in green) between the emitter and collector. (g)band diagram of (f) along the dashed line. In each band diagram, the brown solid arrowsshow the electron path from being excited in the emitter to the collector. The red dashedarrows show carrier relaxation due to e-e scattering. The grey dashed arrows denote theback transfer from the collector to the emitter.4When an ultra-thin layered semiconductor replaces the bulk semiconductor (Figure 1c),and the photocarriers are extracted laterally, there is an additional mechanism that furtherplagues the quantum efficiency of the photodetector, as explained using the band diagramsin Figure 1d-e. These two band diagrams are plotted along the lateral dashed black lineand the vertical dashed magenta line in Figure 1c. Note that the electric field exponentiallydrops in the lateral direction within a transfer length (LT ) from the metal-semiconductorcontact edge,46–49 as marked by the dashed box in Figures 1c-d - degrading the drift of thephoto-generated electrons under the metal-semiconductor overlap area. In addition, beingthe energetically favourable process, in the vertical direction, the photo-induced carriersinjected from metal to the layered material are transferred back to the metal at a fasttimescale (τsm) (see Figure 1e). τsm is far shorter than the time (τl) it takes for the carrier totraverse the lateral metal-semiconductor overlap area. This results in poor carrier injectionefficiency unless the photocarrier is generated adjacent to the metal-semiconductor edge.40,46This effectively reduces the active area of the photodetector, eventually resulting in a weakphotoresponse.Proposed device structure: To circumvent these problems, we propose to use anasymmetric double heterostructure with a thin barrier layer being sandwiched between theemitter (carrier injector) and the collector layers (Figure 1f). Unlike a typical Schottkybarrier diode, the collector conduction band (CB) edge is chosen to be energetically lowerthan the emitter, as shown in Figure 1g. The proposed structure has several importantfeatures: (a) The light absorption occurs in a doped semiconductor instead of a metal, andwe show later that the interplay between the availability of free electrons and e-e scatteringdictates an optimum doping condition that provides the maximum photoresponse. A gatevoltage tunes the electrostatic doping in the absorbing layer. (b) The band-offsets of theconstituting layers are chosen so that the heterojunction acts as a valve. Once the hotelectrons are transferred from the emitter layer to the collector layer and relax to the bandedge, the back transfer probability is minimal due to the high energy cost. Note that fast5MoS2WSe2WS2AuFLGSiO2h-BN(a) (c) (e)(b) (d)E CGE CECGG(g)(h)MoS2 (C)Au (E)EFCBCBWSe2WS2 (E)CBMoS2 (C)(f)WS2Au (C)EFCBMoS2 (E)D3(dark)D3VG = -1:1:3 VD3(dark)VG = 0:1:5 VD2(dark)Collector Bias [V]Collector Current [A](i) (j)Figure 2: Proposed structure and relative performance: (a) Schematic representationof D1, MoS2-Au device without any barrier layer. (b) Band diagram of the conductionband (CB) edge of D1. (c) Schematic of D2, WS2/WSe2/MoS2 device where the WSe2barrier layer is sandwiched between the WS2 emitter and MoS2 collector. The two layersare contacted using a few-layer graphene (FLG). (d) Band diagram of the conduction bandedge of D2. (e) Schematic of D3, MoS2/WS2/Au device with MoS2 emitter and Au collector.(f) Band diagram of the conduction band edge of D3. Gate (G), emitter (E) and collector(C) terminals are indicated in each schematic. The strength of the photoelectron flux indifferent directions is shown by the width of the corresponding arrows in band diagrams.(g) Comparative photocurrent of the device structures D1, D2 and D3 at similar incidentpower (1550 nm). (h) Gate bias dependent collector current characteristics of D2 (left panel)and D3 (right panel) as a function of collector bias under dark conditions. (i) Temperature-dependent collector current characteristics of D3 as a function of collector bias under darkconditions. (j) Arrhenius plot to extract Schottky barrier height for Au injection (0.16 eV)for the device D3.6carrier relaxation is detrimental in the emitter but is desirable in the collector as it reducesback transfer probability. Thus, choosing a metal as the collector layer further helps toimprove the photoresponse. (c) Note that, in the absence of the barrier layer, the electronsfrom the emitter will be transferred to the lower-energy collector even under dark condition,and the emitter will not be left with sufficient free electron density for the infrared photo-absorption to take place. The energy barrier provided by the barrier layer blocks suchundesirable electron transfer in the dark. (d) The asymmetric band-offsets also help towardsthe unidirectional flow of photocurrent, improving the overall efficiency (indicated by thethickness of arrows in Figure 2b,d,f). (e) The metal also acts as a back reflector for theincident photons, and the thickness of the entire stack is optimized to improve absorption.Results and DiscussionWe perform a systematic study by fabricating three different structures (D1, D2, and D3),as schematically depicted in Figures 2a, c and e (SEM images of D2 and D3 are shownin Supplementary Information S1). Figures 2b, d and f show the corresponding banddiagrams. The thickness of the different layered semiconductors (MoS2, WS2, and WSe2)used is in the range of 5 nm to 15 nm in all the devices (AFM characterization results ofdevices D2 and D3 are provided in Supplementary Information S1.). The details of thefabrication steps are explained in Methods. In D1, we directly place MoS2 on Au film,making a conventional Schottky photodiode. D2 consists of a stack of WS2/WSe2/MoS2layers. The infrared photons excite electrons in the conduction band of the WS2 emitterlayer, which are collected by the MoS2 collector through the WSe2 barrier layer. However,the electrons excited in the MoS2 collector layer find it difficult to cross the barrier due tothe larger barrier height of WSe2. Finally, in D3, a WS2 barrier layer is sandwiched betweenAu collector and MoS2 emitter layers. As shown in Figures 2a, c and e, all three structuresare controlled by a gate voltage (VG).7Figure 2g shows the relative photoresponse of the three structures when excited withthe same optical power (Pop) of 1550 nm radiation. D1 shows no measurable photocurrent(Iph), likely due to strong backscattering, as discussed above (dark current characteristicsof D1 are shown in Supplementary Information S2). D2 and D3 exhibit appreciablephotoresponse; however, Iph from D3 is about 1000-fold stronger than that of D2. Theenhanced structural asymmetry and fast relaxation of the injected carriers in the Au collectorlayer improve the unidirectional flow of Iph in D3 (Figures 2d and f).To understand the difference in asymmetry between D2 and D3, we perform current-voltage characteristics in the dark condition (Figure 2h-i). The results suggest a more diode-like behaviour in D3 compared with D2, which results from stronger asymmetry. Further, weshow the current-voltage characteristics for D3 at different temperatures (Figure 2i). Notethat when the electrons are injected from Au to MoS2 (negative collector bias), there is astrong temperature dependence, indicating thermionic emission. We extract an effective SBHof about 0.16 eV from the temperature dependence,49 as shown in Figure 2j. On the otherhand, when electrons are injected from MoS2 to Au (positive collector bias), the temperaturedependence is negligible, suggesting that the carriers tunnel through the WS2 barrier layer.Engineering the hot electron injection: When illuminated, the electrons in the con-duction band of the emitter layer are excited to higher energy states. These non-equilibriumhigh energy electrons (hot electrons), in turn, relax initially through e-e scattering in anultrafast time scale (τee) and eventually through phonon scattering at a relatively longertimescale (τp).50–52 However, in the van der Waals junctions under consideration, the hotelectrons are also transferred from the emitter to the collector at a fast timescale (τec), withτee < τec < τp.53–56 Thus, in our device, the phonon scattering is essentially filtered out,and the injection efficiency to the collector is primarily controlled by the e-e scattering rate,which, in turn, can be controlled by tuning the free electron density in the emitter layerthrough VG.We plot the VG dependence of Iph for both D2 and D3 in the left and right panels of8(c)Normalized PhotocurrentD2 D3Gate Bias [V]Electron Temperature [K]D3D2(a)Emitter Barrier Collector(d)𝜏𝑒−𝑒𝐶𝜏𝑒−𝑒𝐸(b)Gate Bias [V]Figure 3: Tuning photocurrent through controlling e-e scattering: (a) Photocurrentas a function of gate bias for device structures D2 (left panel) and D3 (right panel). The redstars indicate experimental data, and the blue traces indicate model prediction. The dashedlines show the variation in the fit on changing the simulation parameter (electron tempera-ture) by ±5% (b) Carrier excitation and relaxation for high gate bias (bottom panel, withhigher carrier concentration) and low gate bias (top panel, with lower carrier concentration).The relaxation time (τEe−e) for higher gate bias is lower. The thickness of different arrowsindicates the relative strength of the process. (c) Fitted electron temperature (Te) profile fordevices D2 (left panel) and D3 (right panel) as a function of gate bias. (d) Schematic bandprofiles for two gate biases: low (solid line) and high (dashed line). For each gate bias, theelectron distribution is also shown for low Te and high Te in blue and red traces, respectively.9Figure 3a, respectively. For both the devices, Iph initially increases with an increase in VG,reaching a maximum value, followed by a reduction in Iph with a further increase in VG. Atlarge VG, we again observe a weak increasing trend of Iph with VG. The initial increase inIph is expected due to an increase in the available free electron density that can be excitedto higher energy states by the incoming infrared radiation (see top panel of Figure 3b).However, when the electron density increases significantly (bottom panel of Figure 3b), thefast relaxation due to enhanced e-e scattering tends to quench the hot electron density,reducing the injection efficiency to the collector, thus degrading the net Iph.We develop a simple physical model to explain such nonmonotonic behaviour quantita-tively, as schematically explained in Figure 3d. The details of the model are described inSupplementary Information S3. We solve the Poisson equation along the vertical di-mension to obtain the electrostatic potential of each layer under dark conditions. We assumethat, under illumination, the nonequilibrium electrons available for transfer to the collectorcan be described by Fermi-Dirac statistics with a higher electron temperature (Te) comparedto the lattice temperature (TL). Te is primarily governed by the e-e scattering under thecondition of τee < τec < τp. A higher Te broadens the electron distribution with a longer highenergy tail, thus allowing more electrons to cross the barrier layer (Figure 3d). We use Teas a fitting parameter. The model predicted Iph is shown in solid blue traces in both panelsof Figure 3a, and the corresponding fitted Te is depicted as a function of VG in Figure 3c.Consider the case of small VG in Figure 3d. The conduction band edges are shown in blacksolid lines, and the corresponding electron distribution with and without photoexcitation isshown in blue and red continuous traces, respectively. Both are calculated, keeping the totalelectron concentration in the conduction band fixed. This is achieved by calculating a newquasi-Fermi level under illumination. The broader electron distribution under illuminationallows more carriers to cross the barrier.At higher VG, the free electron density increases under dark conditions, and the bandedges are energetically shifted downward (shown in black dashed lines). This increment in10the available free electron density results in an enhanced Iph (the rising part in Figure 3a).However, with further increase in VG, Te also decreases due to faster e-e scattering (Figure3d), resulting in a narrower electron distribution (dashed traces in blue and red under darkand illumination conditions, respectively), eventually reducing Iph. Figure 3c indicates thatthe fitted Te gradually reduces with VG for both D2 and D3, as expected. With an evenfurther increase in VG, the increase in electron concentration slows down significantly due toscreening, which in turn flattens out Te and results in either flattening or slight incrementin Iph again. The results suggest an intricate way to tune the quantum efficiency of thephotodetector by controlling e-e scattering rate.Infrared photodetection performance: We now focus on device D3 for analyzingthe IR detection performance. To understand the steady-state Iph characteristics under1550 nm excitation, we plot in Figure 4a the device current under laser on (shaded regions)and off conditions at various collector bias (VCE) values. The magnitude of the device currentsystematically increases with VCE. The corresponding photocurrent (Iph = Ilight − Idark) isplotted in Figure 4b. Due to an increased bias, a higher electric field helps the electronsexcited in the emitter layer to quickly escape to the collector before relaxation, increasingIph. However, due to an increase in Idark, larger VCE also increases the shot noise (andthermal noise as well due to substrate heating), as clearly observed in Figure 4b.The corresponding responsivity (R = Iph/Pop at VCE = 4 V) is plotted in Figure 4c asa function of incident optical power (Pop), showing a maximum R of 42 mA/W. Note that,unlike typical 2D material-based photodetectors where R changes by order of magnitudewith a variation in Pop, in our device, R remains a relatively weak function of Pop. Thissuggests a negligible role of photocarrier recombination and trapping effects in the devicephotocurrent.We extract the noise amplitude (N) from the low-frequency temporal response of D3(Figure 4a) by calculating the standard deviation of the device current under optical illu-mination. The corresponding signal-to-noise ratio (SNR =IphN) is plotted in Figure 4d as a11Collector Current [µA](a) (b)(c)VCE = 4 VVCE = 2 VVCE = 1 VNormalized Photocurrent(e)(d)Figure 4: Infrared detection performance of D3: (a) Collector current of device D3with periodic optical (1550 nm) excitation. Grey bands indicate the duration when theoptical excitation is on. (b) Collector bias dependence of photocurrent, as extracted from(a). (c) Responsivity (R) of the photodetector as a function of input power at a collectorbias of 4 V. (d) The detector’s signal-to-noise ratio (SNR) as a function of input power at acollector bias of 4 V (red triangles), 2 V (green dots) and 0.1 V (blue stars). (e) Normalizedphotocurrent at zero collector bias at various NIR wavelengths.function of Pop, for different VCE. Interestingly, at low Pop, we obtain higher SNR at VCE = 2V compared with VCE = 4 V due to enhanced shot noise at higher bias. This suggests thatan optimal VCE exists for weak signal detection to maximize SNR.The photoresponse of D3 is nearly flat from 1100 nm to 1800 nm excitation (Figure 4e).A similar broad response is obtained from D2 as well (see Supplementary InformationS4). This broad response arises because the photon energy at this wavelength range issignificantly higher than the band offset between the emitter and the barrier layer. Theresults from another fabrication run of D3 are shown in Supplementary Information S5.Some more devices with thicker emitter (MoS2) layers are also tested to understand if12thicker emitter layers would help in improved IR absorption. However, we observe that adevice with about 50 nm emitter thickness exhibits a poor response (see SupplementaryInformation S6), while another one with about 100 nm emitter layer thickness does notshow any discernible photoresponse. This is likely due to a relaxation of the photocarriersbefore reaching the barrier layer interface and underlines the need for an optimum emitterlayer thickness.Time [ms]RLRDVBIAS VDDBPF(a)(b)(c)G VOUTCEFigure 5: System integration and speed of operation: (a) Circuit diagram representingthe setup to measure the frequency response. Inset: The 2D photodetector chip (in bluecolour at the centre) integrated into a PCB with other off-chip electronics. (b) Temporalresponse of the detector D3 from 100 Hz to 30 kHz. Signal above the noise floor can beobserved up to 30 kHz. (c) Relative response [VOUT (f)/VOUT (100 Hz)] of the device D3 indB as a function of laser modulation frequency.Next, we measure the frequency response of D3 using a setup shown in Figure 5a. The13detector is connected to a VBIAS = −4 V through an external load resistor (RL) of 570 kΩ,which helps convert the output current to a voltage signal. The signal from the photodetectoris fed to a JFET-based single-stage amplifier with a load resistance (RD) of 100 Ω. The JFETis biased with a VDD = 3 V. The detector, external resistors and the JFET are integratedinto a printed circuit board (PCB) (inset of Figure 5a). The signal output is then furtherbandpass-filtered with an input gain of 20 dB and observed in an oscilloscope.The photodetector is illuminated with a 1550 nm laser at varying frequencies. Thetemporal response of the output signal for different laser modulation frequencies is shown inFigure 5b. The time during which light is illuminated is shown in grey bands in the top leftpanel. A signal above the noise floor could be observed up to ∼30 KHz. Figure 5c showsrelative photoresponse (in dB) as a function of the laser intensity modulation frequency.The measured frequency response is primarily limited by the gain-bandwidth product ofthe external measurement setup and not by the intrinsic device. The limiting factor arisesfrom the relatively large input capacitance of the JFET. The intrinsic response from thedevice itself could be much faster, as all the physical processes involved in the detectionmechanism are fast. In Supplementary Information S7, we show the device’s responseto 633 nm excitation (which allows bandgap absorption and hence a stronger signal), demon-strating a detectable response above the noise floor up to 100 KHz. A table benchmarkingour device performance with other works is given in Supplementary Information S8.ConclusionTo conclude, we demonstrate efficient broadband infrared response using a different classof intra-band photodetector where the internal quantum efficiency is intrinsically improvedthrough elegant hot electron management. The simplicity of the design makes the devicereadily integrable with different photo-excitation schemes, such as with a waveguide. We alsodemonstrate the heterogeneous integration of the photodetector chip with post-processing14electronics on a printed circuit board, making it immediately usable at a system level.MethodsDevice fabrication and characterization: First, contacts are defined by optical lithog-raphy on a 285 nm thermally grown SiO2 coated Si substrate. This is followed by Ti (20nm) and Au (40 nm) deposition by DC sputtering and lift-off. Then, layers of each materialof appropriate thickness for the respective devices are exfoliated on a PDMS stamp andtransferred sequentially on the pre-patterned substrate. Finally, the devices are annealed at150oC in a vacuum (10−6 Torr) for three hours to form good contacts.DC electrical and optical characterization of the devices is performed under vacuum(10−4 Torr) in Lakeshore CRX-6.5K probe station equipped with an optical fibre probe. Forfrequency response measurement, the substrate with the device is wire-bonded on a PCB.The PCB also contains an n-channel MMBFU310LT1G JFET from Onsemi and surfacemount resistors of appropriate value. The output of the PCB is connected to a digitalstorage oscilloscope through a gain stage and a bandpass filter.The photocurrent of the device has been measured by shining light on the device using afibre of 100 µm diameter. The device is kept at a distance of about 50 µm from the deviceat an oblique angle of about 30o. The power of the light coming out is measured using apower meter. Since the spot size (Afiber) from the fibre is much larger than the device area(Adevice), the responsivity is calculated asR =PopIPhAfiberAdevice(1)AcknowledgementsK.M. acknowledges useful discussion with Andrew Lord. K.M. acknowledges the supportfrom a grant under SERB TETRA, grants from Indian Space Research Organization (ISRO),15a grant from British Telecom India Research Centre (BTIRC), a grant from I-HUB QTF,IISER Pune, and a seed funding under Quantum Research Park (QuRP) from Karnataka In-novation and Technology Society (KITS), K-Tech, Government of Karnataka. K.W. and T.T.acknowledge support from the JSPS KAKENHI (Grant Numbers 21H05233 and 23H02052)and World Premier International Research Center Initiative (WPI), MEXT, Japan. S.T. ac-knowledges primary support from DOE-SC0020653 (materials synthesis), Applied MaterialsInc., NSF CMMI 1825594 (NMR and TEM studies), NSF DMR-1955889 (magnetic mea-surements), NSF CBET 2206987, DMR 2111812, and CMMI 2129412, and support fromLawrence Semiconductors.Competing InterestsThe authors declare no competing financial or non-financial interests.Associated ContentData Availability StatementThe data supporting this study’s findings are available from the corresponding author uponrequest.Supporting InformationThe Supporting Information is available free of charge at XXX. SEM and AFM data of de-vices D2 and D3, electrical characteristics of device D1 under dark conditions, hot-electroninduced photocurrent model, the response of structure D2 to various wavelengths, characteri-zation of additional D3 device, MoS2 thickness-dependent photoresponse of D3, the frequencyresponse of D3 for excitation with 633 nm radiation and performance benchmarking.16References(1) Kaushal, H.; Kaddoum, G. Optical Communication in Space: Challenges and Mitiga-tion Techniques. IEEE Communications Surveys & Tutorials 2017, 19, 57–96.(2) Hui, R. Introduction to Fiber-Optic Communications ; Academic Press, 2019.(3) Lee, S. J.; Ku, Z.; Barve, A.; Montoya, J.; Jang, W.-Y.; Brueck, S.; Sundaram, M.;Reisinger, A.; Krishna, S.; Noh, S. K. A monolithically integrated plasmonic infraredquantum dot camera. Nature Communications 2011, 2, 286.(4) Yeh, K.; Sharma, I.; Falahkheirkhah, K.; Confer, M. P.; Orr, A. 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