Fabrication of cerium-doped β-Ga_2O_3 epitaxial thin films and deep ultraviolet photodetectors

Abstract

High-quality cerium-doped β-Ga₂O₃ (Ga₂O₃:Ce) thin films could be achieved on (0001)α-Al₂O₃ substrates using a pulsed-laser deposition method. The impact of dopant contents concentration on crystal structure, optical absorption, photoluminescence, and photoelectric properties has been intensively studied. X-ray diffraction analysis results have shown that Ga₂O₃:Ce films are highly (2¯01) oriented, and the lattice spacing of the (4¯02) planes is sensitive to the Ce doping level. The prepared Ga₂O₃:Ce films show a sharp absorption edge at about 250 nm, meaning a high transparency to deep ultraviolet (DUV) light. The photoluminescence results revealed that the emissions were in the violet-blue-green region, which are associated with the donor-acceptor transitions with the Ce³⁺ and oxygen vacancies related defects. A simple DUV photodetector device with a metal-semiconductor-metal structure has also been fabricated based on Ga₂O₃:Ce thin film. A distinct DUV photoresponse was obtained, suggesting a potential application in DUV photodetector devices.