In-situ growth of vertically stacked 2D SnS 2 /SnS heterostructure for highly sensitive and rapid room temperature NO 2 gas sensor

Construction of 2D heterostructure is a potential strategy to improve the sensing performance of 2D layered materials owing to the high -quality of heterointerfaces. This attributed to the remarkable electronic band alignment between the constituent materials and their distinctive characteristics. Woefully, very limited attempts have been taken to investigate the effect of 2D heterointerface for gas sensing applications. Here, the SnS 2 /SnS heterostructure is fabricated on a SiO 2 /Si substrate using a single-step atmospheric chemical vapor deposition technique for room temperature NO 2 sensing. The heterostructure has imparted a 1.3 times enhancement in response ( S (%)), with ultra -fast response ( tau res ) and recovery time ( tau rec ) of 32 s and 382 s, towards 40 ppm of NO 2 at 30 degrees C. Moreover, the impact of humidity on the sensing performance of SnS 2 /SnS has also been studied, confirming its negligible effect on relative humidity. Additionally, it also demonstrates a remarkable stability of 93% over a period of 40 days. Besides, due to strong adsorption energy of SnS 2 (1914 meV) and SnS (600 meV) towards NO 2 endorses the reaction kinetic parameters validated by the gas adsorption/desorption isotherm analysis of heterostructure. The substantial interface contacts between the SnS 2 /SnS heterostructure facilities the fermi -level mediated charge transfer, contributing significantly towards the improvement in sensing performance. Therefore, the formation of hierarchical 2D heterostructure with electron depletion layer can be considered as a conducive way for the future development low -powered gas sensor.