Study on sensing characteristics of NH3 on ( −2 0 1) β-Ga2O3 surface

Abstract

In this paper, the adsorption characteristics of NH3 on (−201) β-Ga2O3 were studied by using density functional theory. From the results of adsorption energy and binding energy, it can be seen that for the Ga surface, the combination of NH3 and the surface is weak, and even model B is an endothermic reaction. For the O surface, NH3 can not only spontaneously proceed on its surface, but also combine firmly, indicating that NH3 is easy to react with the O surface. Density of states analysis showed that NH3 molecules adsorbed on the (−201) β-Ga2O3, resulting in great changes in the characteristics of semiconductors. Charge analysis make it clear that, unlike the physical adsorption formed on the Ga surface, NH3 forms NO chemical bonds with the O surface. Bader charge analysis indicate that the amount of charge transfer between O surface and NH3 molecules is the largest. The above results imply that the O surface is suitable for the surface of NH3 sensor. Compared with model C, model D has the largest amount of charge transfer, and the sensor prepared with it has higher sensitivity, so it is the most suitable NH3 sensor surface.