UV-enhanced exfoliated MoS2/PtSe2 heterostructure for ultra-sensitive NO2 detection at room temperature

We report a MoS2/PtSe2 heterostructure-based gas sensor for detecting trace levels of NO2 gas at room temperature. Both MoS2 and PtSe2 were synthesized by mechanical exfoliation, and the heterostructure was prepared using deterministic dry transfer method. Comprehensive characterization was performed using optical microscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, high resolution transmission electron microscopy, Raman spectroscopy and atomic force microscopy. The lateral shape of the heterostructure efficiently adsorbed NO2 molecules. The sensor exhibited limited response and recovery in dark conditions. However, under UV illumination, the sensor showed remarkable response of 2180% and 117% towards 800 ppb and 50 ppb NO2, respectively, with complete recovery. The theoretical limit of detection was found to be 3 ppb, and the sensitivity towards NO2 sensing was 3.217% ppb−1, which is noteworthy. Furthermore, the sensor demonstrated distinct selectivity, excellent repeatability and stability. These findings are expected to significantly advance ongoing research on TMDC-based heterostructures for gas sensing application.