All polymer encapsulated, highly-sensitive MoS2 phototransistors on flexible PAR substrate

Abstract

We have demonstrated electrically and optically enhanced MoS2 phototransistors on a flexible polyarylate substrate using poly(4-vinylphenol) (PVP) as a gate dielectric as well as an encapsulation layer. With the PVP encapsulation, the field-effect mobility (μFE) increases up to twofold, and the subthreshold slope as well as the on/off ratio (ION/IOFF) improves, which are desirable features for the photoresponsive characteristics. Consequently, both photoresponsivity and detectivity increase up to two orders of magnitude (×100) from visible to infrared spectrum. Such enhancement is associated with the n-doping effect of hydroxyl groups in PVP and reduced recombination centers by filling interface traps and surface states. Our results reveal that the transparent PVP polymer can be a promising encapsulation method in order to enhance the electrical and photoresponsive characteristics of MoS2-based flexible devices.

A review of molybdenum disulfide (MoS2) based photodetectors: from ultra-broadband, self-powered to flexible devices

“…294 MoS 2 phototransistors have been prepared on exible polyarylate substrate where poly(4-vinylphenol) (PVP) was used both as a gate dielectric and an encapsulating layer material. 295 The encapsulation with PVP improved the eld-effect mobility (m FE ) and the current I on /I off ratio, which resulted in two orders of magnitude enhancement in photoresponsivity as well as in detectivity from visible to infrared wavelength. The hydroxyl functional groups in PVP improved the performance of MoS 2 phototransistors due to the n-doping effect and decreased the recombination of photoexcited carriers.…”

“…The inuence of different types of substrate materials on the performance of MoS 2 photodetectors has been extensively studied. 164,178,184,[217][218][219][220]222,223,234,256,259,278,298,[311][312][313] MoS 2 @TiO 2 core-shell heterojunction-based photodetectors were prepared by Paul et al 320 where 1L MoS 2 was used as the shell and TiO 2 nanoowers as the core. The 83 and 30 times increase in PL intensity was observed from the 1L MoS 2 shell/ TiO 2 nanoowers p-n heterojunction more than that of 1L MoS 2 /Ti and 1L MoS 2 /sapphire substrates, respectively.…”

High-performance flexible nanoscale transistors based on transition metal dichalcogenides

“…Together with further optimization of electrostatic control (thinner gate dielectrics or double-gates) and reduced parasitics (e.g., lower RC) these results provide a promising outlook for incorporating flexible TMD electronics in low-power and high-performance IoT applications. 4,16,17,29,[40][41][42][43][44][45][46][47][48][49] . Three studies reported µFE excluding contact resistance with the y-function method ("YF").…”

“…Displaying µFE,ext and ID (at VDS = 1 V, unless noted otherwise) for flexible MoS2 FETs vs. L (Fig. 4a,b) reveals that nanoscale devices have received little attention until now (values listed in Supplementary TableS1)4,16,17,29,[40][41][42][43][44][45][46][47][48][49] . Fig.4ccompares the on-current and on/off ratio of the few ex-…”

Molecular Functionalization of 2d Materials

“…Other studies of polymer-TMDC interactions report properties such as increased photoresponsivity, 70 and improved mechanical and thermal stability 71 of MoS2 by polymer encapsulation.…”