Two-dimensional GeSe monolayer doped with single main-group element atom for hazardous gas detection: A first-principles study

Abstract

Currently, the identification of sensing materials that can selectively and rapidly respond to hazardous gases is urgent for safeguarding the environment and human life. The adsorption of hazardous gas molecules (NO, NO2, SO2, CO, and H2S) on the GeSe monolayer doped with single main-group element atom is investigated and compared based on first-principles density functional theory (DFT). NO2 has the highest adsorption energy and charge transfer adsorbed on both pristine GeSe and doped GeSe monolayer. At ambient temperature, for any doped GeSe monolayers adsorbing gas molecules (including H2O, O2, and N2), the occupation function value of NO2 is the highest. The analysis of density of states (DOS) and band structure indicates that NO2 interacts with different modified GeSe monolayers in terms of atomic orbitals. Moreover, Al-GeSe has the largest change of work function before and after the adsorption of NO2, meaning that Al-GeSe has the greatest response to NO2. current-voltage (I-V) characteristics demonstrate that Al-GeSe exhibits a remarkable current change after the adsorption of NO2. These results illustrate that Al-GeSe has a strong physical and chemical interaction with NO2, yielding a high response and selectivity, which is anticipated to be the optimal gas sensing material for NO2.