Dilute-selenium alloying: A possible perspective for achieving p-type conductivity of β-gallium oxide

Photoconductive and heterojunction devices prepared based on n-type β-Ga2O3 have been extensively studied in the field of solar-blind ultraviolet (UV) detectors. However, for exploiting the full potential of photodetection by preparing bipolar homojunction devices, constructing p-type β-Ga2O3 through rational design remains a challenge. Herein, a p-type β-Ga2(SexO1−x)3 thin film was successfully prepared by a dilute-selenium alloying process. The bandgap was effectively regulated by varying the Se-content in the films. Meanwhile, the energy offset of valence band maximum and Fermi level is estimated to drop from 3.19 eV to 1.72 eV, indicating a transition of the semiconductor type from n-type to p-type. The β-Ga2(Se0.05O0.95)3 film prepared at the incident power of 120 W exhibited p-type conductivity, which possesses hall hole mobility of 24.3 cm2/V·s, hole concentration of 8.23 × 1014 cm−3, and resistivity of about 310.7 Ωcm at room temperature. This work clarified a possible way to realize p-type β-Ga2O3 by semiconductor alloying.