Solar-Blind Photodetector with High Avalanche Gains and Bias-Tunable Detecting Functionality Based on Metastable Phase α‑Ga2O3/ZnO Isotype Heterostructures
The metastable α-phase Ga2O3 is an emerging material for developing solar-blind photodetectors and power electronic devices toward civil and military applications. Despite its superior physical properties, the high quality epitaxy of metastable phase α-Ga2O3 remains challenging. To this end, single...
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Veröffentlicht in: | ACS applied materials & interfaces 2017-10, Vol.9 (42), p.36997-37005 |
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Hauptverfasser: | , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The metastable α-phase Ga2O3 is an emerging material for developing solar-blind photodetectors and power electronic devices toward civil and military applications. Despite its superior physical properties, the high quality epitaxy of metastable phase α-Ga2O3 remains challenging. To this end, single crystalline α-Ga2O3 epilayers are achieved on nonpolar ZnO (112̅0) substrates for the first time and a high performance Au/α-Ga2O3/ZnO isotype heterostructure-based Schottky barrier avalanche diode is demonstrated. The device exhibits self-powered functions with a dark current lower than 1 pA, a UV/visible rejection ratio of 103 and a detectivity of 9.66 × 1012 cm Hz1/2 W–1. Dual responsivity bands with cutoff wavelengths at 255 and 375 nm are observed with their peak responsivities of 0.50 and 0.071 A W–1 at −5 V, respectively. High photoconductive gain at low bias is governed by a barrier lowing effect at the Au/Ga2O3 and Ga2O3/ZnO heterointerfaces. The device also allows avalanche multiplication processes initiated by pure electron and hole injections under different illumination conditions. High avalanche gains over 103 and a low ionization coefficient ratio of electrons and holes are yielded, leading to a total gain over 105 and a high responsivity of 1.10 × 104 A W–1. Such avalanche heterostructures with ultrahigh gains and bias-tunable UV detecting functionality hold promise for developing high performance solar-blind photodetectors. |
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ISSN: | 1944-8244 1944-8252 |
DOI: | 10.1021/acsami.7b09812 |