High-Responsivity Self-Powered Solar-Blind Photodetectors Based on Magnetron-Sputtered CuCrO $_{\text{2}}$ / $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ p-n Heterojunction

We report for the first time high-performance solar-blind self-powered photodetectors (PDs) based on magnetron-sputtered CuCrO $_{\text{2}}$ / $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ p-n heterojunction. Our CuCrO $_{\text{2}}$ / $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ PDs show a low dark current of 6.5 pA, a high responsivity of 50 mA/W, a high detectivity of 3.7 $\times$ 10 $^{\text{12}}$ Jones, and a high external quantum efficiency (EQE) of 24.6%, which outperform most reported $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ -based heterojunction PDs. Such brilliant performances can be attributed to the high-quality CuCrO $_{\text{2}}$ films enabled by in situ magnetron sputtering, which improve the photogenerated carrier mobility and collection efficiency. Furthermore, type-II band alignment between CuCrO $_{\text{2}}$ and $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ heterojunction is identified by X-ray photoelectron spectroscopy with the valence band offset of 2.61 eV and the conduction band offset of 0.87 eV, which facilitates the separation of photogenerated electrons and holes. These results show that the CuCrO $_{\text{2}}$ / $\beta $ -Ga $_{\text{2}}$ O $_{\text{3}}$ heterojunction could achieve superior solar-blind sensitivity, thus indicating strong prospects in wide practical applications regarding solar-blind detection.