Abstract
Herein, we reported a unique photo device consisting of monolayer graphene and a few-layer rhenium diselenide (ReSe
2
) heterojunction. The prepared Gr/ReSe
2
-HS demonstrated an excellent mobility of 380 cm
2
/Vs, current on/off ratio ~ 10
4
, photoresponsivity (R ~ 74 AW
−1
@ 82 mW cm
−2
), detectivity (D
*
~ 1.25 × 10
11
Jones), external quantum efficiency (EQE ~ 173%) and rapid photoresponse (rise/fall time ~ 75/3 µs) significantly higher to an individual ReSe
2
device (mobility = 36 cm
2
V
−1
s
−1
, Ion/Ioff ratio = 1.4 × 10
5
–1.8 × 10
5
, R = 11.2 AW
−1
, D* = 1.02 × 10
10
, EQE ~ 26.1%, rise/fall time = 2.37/5.03 s). Additionally, gate-bias dependent Schottky barrier height (SBH) estimation for individual ReSe
2
(45 meV at V
bg
= 40 V) and Gr/ReSe
2
-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 defects-free junction. In addition, HS is fully capable to demonstrate an excellent gas sensing response with rapid response/recovery time (39/126 s for NO
2
at 200 ppb) and is operational at room temperature (26.85 °C). The proposed Gr/ReSe
2
-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.