Changes in the Electronic Properties of the GaN/Si(111) Surface under Li Adsorption

The electronic structure of the epitaxial GaN/Si(111) layers and the Li/GaN/Si(111) interface with a monolayer Li coverage has been studied in situ under ultrahigh vacuum conditions. The experiments were carried out using photo electron spectroscopy with synchrotron radiation in the photon energy range 75–850 eV. The photoemission spectra in the valence band and the core levels of Ga 3 d , N 1 s , and Li 1 s are studied for the monolayer Li coating. It is found that Li adsorption causes a significant decrease in the intensity of the photoemission line of the intrinsic surface state and the appearance of an induced surface state due to charge transfer between the adsorbed Li layer and surface Ga atoms. It has been found that the GaN/Si(111) surface has predominantly Ga polarity. The Li/GaN/Si(111) interface has a semiconductor character.