Affiliation:
1. Key Laboratory of UV Light Emitting Materials and Technology Ministry of Education Northeast Normal University Changchun 130024 P. R. China
Abstract
AbstractAn excellent broad‐spectrum (220–380 nm) UV photodetector, covering the UVA‐UVC wavelength range, with an ultrahigh detectivity of ≈1015 cm Hz1/2 W−1, is reported. It is based on a p‐β Ga2O3/n‐GaN heterojunction, in which p‐β Ga2O3 is synthesized by thermal oxidation of GaN and a heterostructure is constructed with the bottom n‐GaN. XRD shows the oxide layer is (−201) preferred oriented β‐phase Ga2O3 films. SIMS and XPS indicate that the residual N atoms as dopants remain in β Ga2O3. XPS also demonstrates that the Fermi level is 0.2 eV lower than the central level of the band gap, indicating that the dominant carriers are holes and the β Ga2O3 is p‐type conductive. Under a bias of −5 V, the photoresponsivity is 56 and 22 A W−1 for 255 and 360 nm, respectively. Correspondingly, the detectivities reach an ultrahigh value of 2.7 × 1015 cm Hz1/2 W−1 (255 nm) and 1.1 × 1015 cm Hz1/2 W−1 (360 nm). The high performance of this UV photodetector is attributed mainly to the continuous conduction band of the p‐β Ga2O3/n‐GaN heterojunction without a potential energy barrier, which is more helpful for photogenerated electron transport from the space charge region to the n‐type GaN layer.
Funder
National Natural Science Foundation of China
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry
Cited by
37 articles.
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