PHOTOELECTRON SPECTROSCOPY STUDIES ON Al2O3 FILMS ON p-GaN(0001)

Abstract

In order to determine its electronic and chemical properties, the Al2O3/p-GaN(0001) interface is studied in situ by the X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS). Using physical vapor deposition (PVD) method, the Al2O3 film is deposited step by step under ultra-high vacuum (UHV) onto p-GaN(0001) surface covered with residual native Ga oxide. Prior to the first Al2O3 layer evaporation, binding energy of the Ga 3[Formula: see text] substrate line is equal to 20.5[Formula: see text]eV. The PVD method of deposition leads to an amorphous Al2O3 film formation. For the final 12.0[Formula: see text]nm thick Al2O3 film binding energy of the Al 2[Formula: see text] line is set at 76.0[Formula: see text]eV and for the O 1[Formula: see text] line at 532.9[Formula: see text]eV. The valence band offset (VBO) and the conduction band offset (CBO) of the Al2O3/p-GaN(0001) interface are determined to be equal to [Formula: see text]1.6[Formula: see text]eV and 1.8[Formula: see text]eV, respectively.