Sensing behavior of modified two-dimensional GeTe monolayer to detect air discharge components: A first-principles study

Abstract

It is crucial to determine the operating condition of air-insulated equipment by monitoring air discharge components (O3, NO2, CO) to detect any occurrence of partial discharges (PD). Although GeTe is widely applied in gas sensing technology, its performance in selective detection is relatively subpar. This study investigatesthe modification of structures of GeTe monolayers by doping single transition-metal (TM) atom (Fe, Co, Ir, Pt, Pd, and Rh) to enhance its gas adsorption capability and selectivity of different doped GeTe monolayers to gases according to competitive adsorption. Multiple properties such as adsorption energy, charge transfer, charge difference density (CDD), density of states (DOS), occupation function, desorption time, and work function were discussed, indicating that doped GeTe exhibits greater adsorption capabilities. Specifically, Ir-GeTe demonstrates the highest absolute value of adsorption energy for O3 at 2.75 eV, while Co-GeTe exhibits the highest absolute value of adsorption energy for NO2 at 2.13 eV. Furthermore, the analysis of atomic orbital overlap reveals stronger chemical interactions between Ir-GeTe and O3, as well as Co-GeTe and NO2. Considering selectivity and working function, Fe-GeTe emerges as a potential sensing material for detecting NO2. This research offers promising and practical applications for single TM atom-doped GeTe as gas-sensitive materials.