First-principle study of gas adsorption on SiGe monolayer as sensor applications

Using first-principles calculation within density functional theory, the adsorption properties of gas (CO 2 , CO, H 2 O, NH 3 ) – SiGe monolayer systems are chosen to investigate and the most sensitive gas and adsorption site (Si site for CO 2 , Center site for CO, Ge site for NH 3 , and Ge site for H 2 O ) are discovered. The adsorption energy, band gap, and charge transfer are all considered. Through research, the results indicate that SiGe is most sensitive to NH3 while H 2 O also show an impressive adsorption property. NH 3 adsorption possess large adsorption energy that is suitable to be used as sensing material in gas device. And the physical adsorption model is determined through considering adsorption distance, adsorption energy, and Charge density difference (CDD) plot, moreover, the physical adsorption is profited to the application of gas sensor. Our theoretical results indicates that monolayer SiGe is a promising candidate for gas sensing applications.