LAUSR

We have electrically investigated deep-level defects in unintentionally-doped β-Ga2O3 single crystal substrates fabricated by an edge-defined film-fed growth method, employing capacitance-voltage (C-V) and steady-state photo-capacitance spectroscopy (SSPC) techniques. From C-V measurements, n-type residual carriers with their concentration of ~8.7 × 1016 cm−3 were almost uniformly distributed over the measured depth region of 188 – 336 nm from the β-Ga2O3 surface. SSPC measurements revealed four dominant deep-level defects located at ~0.8, ~2.04, ~2.71, and ~3.87 eV below the conduction band, in addition to near-band-edge emissions at ~4.49 eV. These deep-level defects tended to be more densely present with shallowing the probing depth range.