Engineered Low‐Oxygen‐Defects in High Formation Energy Ce‐Doped α‐Ga ₂ O ₃ for High‐Performance Solar‐Blind UV Detectors

Abstract Gallium oxide (Ga ₂ O ₃ ), which has an ultra‐wide bandgap (4.4 to 5.3 eV) and possesses advantages including a high breakdown electric field, good thermal stability, and excellent electron mobility, is regarded as an ideal material for fabricating solar‐blind UV detectors. However, there are usually intrinsic oxygen vacancies in Ga ₂ O ₃ crystals, which can lead to an increase in dark current, a decrease in the response speed and efficiency of photodetectors. This work utilizes a simple liquid‐phase epitaxy method to synthesize Ce‐doped α‐Ga ₂ O ₃ films and construct a metal‐semiconductor‐metal Schottky junction detector. The rare earth element Ce and the difference in radius with Ga cause lattice distortion, which in turn affects the formation energy of oxygen defects. Theoretical calculations show that replacing Ga ³⁺ with Ce ³⁺ can suppress the generation of oxygen vacancies through the charge compensation effect. The suppression mechanism of Ce doping on oxygen defects is explored, and it achieves synchronous optimization of device dark current and response speed. Under 5 V bias, the dark current is 2.56 × 10 ⁻⁹ A, the responsivity reached 10.69 A W ⁻¹ , and the detection rate is as high as 6.7 × 10 ¹³ Jones. This work provides a new strategy for achieving high‐performance solar‐blind UV detectors through defect engineering controlled.