2D-MoSe₂/0D-ZnO nanocomposite for improved H₂S gas sensing in dry air ambience

In this paper, we report on a micro-sensor employing two-dimensional (2D)- zero-dimensional (0D) heterostructure based on MOSe₂/ZnO (fabricated by a novel Complementary Metal Oxide Semiconductor (CMOS) compatible microwave-irradiation-assisted solvothermal route) as a receptor. Density Functional Theory (DFT) calculations show that the heterostructure is more favorable to the adsorption of hydrogen sulfide (H₂S) gas than the pristine 2D nanosheets. Experimentally, the device demonstrates sensitivity in the ultra-low concentration H₂S range (i.e. 200 ppb – 6.1 ppm), and response of as high as 9.08% (200 ppb) - 186.91% (6.1 ppm) could be obtained repeatably with decent signal-to-noise ratio and response/recovery time (~600 sec). The device stands well on various sensor parameter tests including absolute response percentage, lower limit of detection (LOD), repeatability, reproducibility, hysteresis error, etc. A sensing mechanism based on Wolkentein's model is proposed to understand the detection behavior of the device.