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.