Self-powered photodetectors based on β-Ga2O3/4H-SiC heterojunction with ultrahigh current on/off ratio and fast response

Solar-blind photodetectors have received increasing attentions due to their widely applications in military and civil aspects. However, most of the photodetectors often suffer from relatively slow response speeds and high driving voltages. Therefore, it is desirable to develop the self-powered photodetectors with a fast response speed. In this manuscript, self-powered and fast response photodetectors based on beta-Ga2O3/4H-SiC pn heterojunction are demonstrated by depositing beta-Ga2O3 films on p-type 4H-SiC templates using Pulse Laser Deposition method. The detectors exhibit an ultrahigh current I-on/I-off ratio more than 10(3) (similar to 1655) at the light intensity of 91 mu W/cm(2) and a fast photo-response speed (a rise time of 11 ms and a decay time of 19 ms) under zero-bias voltage, which are attributed to the quickly separation of the photogenerated electron-hole pairs driven by the built-in electric field at the interface of beta-Ga2O3/4H-SiC pn heterojunction. In addition, the detectors also show a responsivity of 10.35 mA/W with a high detectivity of 8.8 x 10(9) Jones, and the maximum linear dynamic range is reached 64.38 dB. The generality of the above excellent results suggests that the beta-Ga2O3/4H-SiC pn photodetectors have great potential in UV detection. Finally, the electronic transport mechanism of the beta-Ga2O3/4H-SiC pn heterojunction has been analyzed with the energy band diagram. (C) 2019 Elsevier B.V. All rights reserved.