Surface morphology and electronic structure of bulk single crystal β-Ga2O3(100)

Experimental studies of the surface morphology and electronic structure of bulk single crystals of the transparent and wide gap semiconductor gallium oxide (β-Ga2O3) have been conducted using scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and angle-resolved photoemission spectroscopy (ARPES). Atomically resolved STM and LEED results for the β-Ga2O3(100) surface clarify that the predominant surface termination contains both gallium and oxygen, and this surface does not exhibit a reconstruction. The valence band structure was obtained with ARPES and shows good agreement with existing theoretical works at the zone center and along the a∗ and c∗ directions, except that the calculated bandwidth is ∼7% too small. There is poorer agreement along the b∗ direction, where the experimental bands disperse more strongly than the calculations.