Cs adsorption onβ-Ga203 (100) surface: a first-principles research

Abstract

Based on density functional theory (DFT) and first-principles method, the feasibility of using 𝛽-𝐺𝑎2𝑂3 to make vacuum ultraviolet photocathode was studied. Eight Cs adsorption sites are chosen for the 𝛽-𝐺𝑎2𝑂3(100) surface. The adsorption energy, work function, energy band structure of 8 adsorption sites and the change of work function under different Cs coverage are calculated. The results show that the adsorption energy at all sites decreases significantly. It can be concluded that the 𝛽-𝐺𝑎2𝑂3(100) surface satisfies the necessary conditions for Cs/O activation. In addition, different cesium adsorption concentrations have an effect on the surface work function, and the overall trend is that it decreases at first and then increases. Finally, the properties of energy bands under different coverage are analyzed. The results show that the widely used method of cesium adsorption to reduce the work function is also suitable for 𝛽-𝐺𝑎2𝑂3 materials.