Energy-Band Parameters at the GaAs- and GaN-Ga sub 2 O sub 3 (Gd sub 2 O sub 3) Interfaces

The valence-band offset ( DELTA E sub V) has been determined to be ~2.6 eV at the Ga sub 2 O sub 3 (Gd sub 2 O sub 3 )-GaAs interface, and ~1.1 eV at the Ga sub 2 O sub 3 (Gd sub 2 ) sub 3 )-GaN interface by high-resolution x-ray photoelectron spectroscopy with synchrotron radiation beam. The Pt-Ga sub 2 O sub 3 (Gd sub 2 O sub 3 )-GaAs MOS diode exhibits a current-voltage characteristic dominated by Fowler-Nordheim tunneling. From the current-voltage data at forward and reverse biases, we have extracted a conduction-band offset ( DELTA E cub C ) of ~1.4 eV at the Ga sub 2 O sub 3 (Gd sub 2 O sub 3)- GaAs interface and an electron effective mass m ~ 0.29 m sub e of the Ga sub 2 O sub 3 (Gd sub 2 O sub 3 ) layer. Consequently, the energy-band gap of Ga sub 2 O sub 3 (Gd sub 2 O sub 3 ) is ~5.4 eV, while DELTA E sub C for the Ga sub 2 O sub 3 (Gd sub 2 O sub 3)-GaN interface is ~0.9 eV.