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

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 (mu(FE)) increases up to twofold, and the subthreshold slope as well as the on/off ratio (I-ON/I-OFF) improves, which are desirable features for the, photoresponsive characteristics. Consequently, both photoresponsivity and detectivity increase up to two orders of magnitude (x 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. Published by AIP Publishing.