First principles study of the gas sensing 2D GeTe: atomic, electronic and transport properties

Abstract

2D GeTe has been predicted to be a promising ferroelectric and channel material due to its excellent electronic, optical, and excitonic properties. Here, using density functional theory in combination with the non-equilibrium Green's function method, we demonstrate the potential application of GeTe in NO sensor. It is found that the top sites of Ge atoms are the preferential adsorption sites for all considered gas molecules. The calculated adsorption energy of NO molecule is the largest, which is explained by both the quantitative Bader charge results and the charge density difference and electron localization function. The high selectivity and sensitivity of the 2D GeTe to NO molecule are demonstrated through comparing the band structures and density of states of GeTe before and after molecules adsorption. The distinct I–V responses show a significant current increase after the adsorption of NO, confirming the high sensitivity and selectivity for NO detection. A faster recovery speed of GeTe comparing to other sensors is also demonstrated. Our results highlight the potential application of GeTe as an efficient gas sensor for identifying NO molecules.