Built-in electric fields and interfacial state densities (Dit) in a series of oxide-GaAs heterostructures fabricated by in situ molecular beam epitaxy were studied using room temperature photoreflectance. The samples investigated were air-, Al2O3-Ga2O x-, and Ga2O3(Gd2O 3)-GaAs. We found that the built-in electric fields are 48, 44, and 38 kV/cm for air-, Al2O3-, and Ga2O x-GaAs samples, respectively. For the Ga2O 3(Gd2O3)-GaAs sample, the built-in electric field is negligibly small, indicating a very low interfacial state density. Estimated by the low field limit criterion, D it is less than 1 × 10 11 cm-2 eV-1. Our results on the Ga 2O3(Gd2O3)-GaAs sample are consistent with the data obtained previously using capacitance-voltage measurements in quasistatic/high frequency modes and photoluminescence measurements.
All Science Journal Classification (ASJC) codes
- 物理與天文學 (全部)