MoS₂ Phototransistor Sensitized by Colloidal Semiconductor Quantum Wells

Abstract

A phototransistor built by the assembly of 2D colloidal semiconductor quantum wells (CQWs) on a single layer of 2D transition metal dichalcogenide (TMD) is displayed. This hybrid device architecture exhibits high efficiency in Förster resonance energy transfer (FRET) enabling superior performance in terms of photoresponsivity and detectivity. Here, a thin film of CdSe/CdS CQWs acts as a sensitizer layer on top of the MoS2 monolayer based field‐effect transistor, where this CQWs–MoS2 structure allows for strong light absorption in CQWs in the operating spectral region and strong dipole‐to‐dipole coupling between MoS2 and CQWs resulting in enhanced photoresponsivity of one order of magnitude (11‐fold) at maximum gate voltage (VBG = 2 V) and two orders of magnitude (≈ 5 × 102) at VBG = −1.5 V, and tenfold enhanced specific detectivity. The illumination power‐dependent characterization of this hybrid device reveals that the thin layer of CQWs dominates the photogating mechanism compared to the photoconductivity effect on detection performance. Such hybrid designs hold great promise for 2D‐material based photodetectors to reach high performance and find use in optoelectronic applications.

2D layered SiP as anisotropic nonlinear optical material

“…The era of 2D layered materials, also known as van der Waals materials, has begun by the exfoliation of bulk graphite into monolayer graphene with extraordinary properties 1 . Beyond graphene, 2D materials such as transition metal dichalcogenides (TMDs) like MoS 2 and WSe 2 , halides (MX 2 with X being Cl, Br, I 2 ) and carbides/nitrides (MXenes 3 – 5 ) have gained more attraction due to their superior electrical, optical, mechanical, thermoelectric, energy storage and sensing properties. Owing strong light-material interaction with broad spectral coverage range and tunable band gap, 2D materials are endorsed as promising optical materials.…”

Förster Resonance Energy Transfer Assisted Enhancement in Optoelectronic Properties of Metal Halide Perovskite Nanocrystals

“…Sar et al reported higher photoresponsivity and detectivity in phototransistor from the hybrid structure of FRET-enabled 2D-MoS 2 and CdSe quantum well. 12 These FRET-based multiband systems enable selective higher extinction, passivation of interfacial recombi-nation, longer exciton diffusivity, and effective use of the excited charge carriers before recombination. While a plethora of literature on different semiconductor devices with D−A systems has been reported, studies on FRET-enabled optoelectronic devices with PNCs are limited.…”

“…Not just limited to solar cells, FRET-enabled superior performance is also reported for phototransistor and light-emitting diodes. Sar et al reported higher photoresponsivity and detectivity in phototransistor from the hybrid structure of FRET-enabled 2D-MoS 2 and CdSe quantum well . These FRET-based multiband systems enable selective higher extinction, passivation of interfacial recombination, longer exciton diffusivity, and effective use of the excited charge carriers before recombination.…”

GaS:WS2 Heterojunctions for Ultrathin Two-Dimensional Photodetectors with Large Linear Dynamic Range across Broad Wavelengths

“…It should be noted that for Schottky-type contacts, the strong illumination power leads to increased electric field in the channel due to the lowered Schottky barrier height. However, the increase in electric field alone can hardly compensate for the exponential decayed carrier lifetime in previous reports; ,, thus, an increase in mobility is essential for further tuning the photoresponse-power relation.…”

“…The obtained high LDR for the WS 2 /GaS 0.87 heterostructure photodetector is larger than 73 dB, which surpasses that of many other 2D heterostructure photodetectors and commercial photodetectors such as GaN (50 dB) and InGaAs (66 dB). ,,− It should be noted that a higher irradiance power might induce subtle damage to the WS 2 layer exposed to air, as the monolayer WS 2 devices also exhibit weakened performance after that; therefore, the measured LDR can be further improved with inert atmosphere protection. In Figure i, the figures of merit of the photodetectors based on type-II heterostructures are summarized with photoresponsivity in x -axis and LDR in y -axis. ,− ,,,,− While devices based on PVE show a high LDR of 53–132 dB, the photoresponsivity value is less than 0.5 A/W. Other devices based on PGE or conventional sensitizers do not show linearity, and the photoresponsivity value often decays to under 10 A/W under high-power irradiance.…”