Bias-Modified Schottky Barrier Height-Dependent Graphene/ReSe2 van der Waals Heterostructures for Excellent Photodetector and NO2 Gas Sensing Applications

Herein, we reported a unique photo device consisting of monolayer graphene and a few-layer rhenium diselenide (ReSe2) heterojunction. The prepared Gr/ReSe2-HS demonstrated an excellent mobility of 380 cm(2)/Vs, current on/off ratio similar to 10(4), photoresponsivity (R similar to 74 AW(-1)@ 82 mW cm(-2)), detectivity (D * similar to 1.25 x 10(11) Jones), external quantum efficiency (EQE similar to 173%) and rapid photoresponse (rise/fall time similar to 75/3 mu s) significantly higher to an individual ReSe2 device (mobility = 36 cm(2) v(-1) s(-1) f Ion/Ioff ratio = 1.4 x 10(5) -1.8 x 10(5), R = 11.2 AW(-1), D*= 1.02 x 10(10), EQE similar to 26.1%, rise/fall time = 2.37/5.03 s). Additionally, gate-bias dependent Schottky barrier height (SBH) estimation for individual ReSe2 (45 meV at V-bg = 40 V) and Gr/ReSe2-HS (9.02 meV at V-bg = 40 V) revealed a low value for the heterostructure, confirming dry transfer technique to be successful in fabricating an interfacial defectsfree junction. In addition, HS is fully capable to demonstrate an excellent gas sensing response with rapid response/recovery time (39/126 s for NO2 at 200 ppb) and is operational at room temperature (26.85 degrees C). The proposed Gr/ReSe2-HS is capable of demonstrating excellent electro-optical, as well as gas sensing, performance simultaneously and, therefore, can be used as a building block to fabricate next-generation photodetectors and gas sensors.

Automated summary

This study reported a photo device composed of monolayer graphene and few-layer rhenium diselenide (ReSe2) heterojunction, demonstrating excellent performance in terms of mobility, photoresponsivity, gas sensing response, etc.