“…For the (101 ¯0) UID Ga 2 O 3 layers, the E go fitted under the assumption of the indirect and direct transitions were 4.78 and 5.31 eV, respectively. The E ind,go of 4.78 eV is much smaller than the theoretical values of 5.34 eV 2) and the values determined by spectroscopic ellipsometry (5.6 eV, 22) 5.62 eV 39,40) ), transmission spectra (5.3 eV), 9,41) and X-ray photoelectron spectroscopy (XPS) (5.3 eV, 42) 5.41 eV 5) ). The measured absorption spectrum might be dominated by directlike energy band absorption.…”