Photo-induced conductivity transient in n-type β-(Al_0.16Ga_0.84)₂O₃ and β-Ga₂O₃

Abstract Photo-induced conductivity transients are reported for unintentionally doped (UID) β-Ga2O3 and n-type β-(Al0.16Ga0.84)2O3. The illumination of (UID) β-Ga2O3 and β-(Al0.16Ga0.84)2O3/Ga2O3 heterojunction with a sub-bandgap light ranging from 400 to 1000 nm (1.2–3.1 eV) increases their conductivity. The increase in the conductivity still remains after the light is turned off, and then slowly exhausts. From the transient photoconductivity, the optical cross-sections of the photo-ionized defects have been measured as a function of the photon energy, and the optical absorption peaks of the ionized defects have been calculated. Thus, the measured photoconductivity in both β-Ga2O3 and (Al0.16Ga0.84)2O3 are induced by broad optical absorption peaks that have been estimated to be 2.52–2.88 eV and 2.61–3.11 eV.