Suppression of decay time in transient drain current of back-gated GaN HEMT under UV exposure

Abstract

Abstract Photodetectors based on an AlGaN/GaN high electron mobility transistor on Si have a long decay time after removal of light irradiation because of the large number of defects. This behavior is unsuitable for applications that require fast response. In several papers, though decay time was suppressed by thermal heating, it has problems such as fabrication complexity and power consumption. In this paper, we propose a substrate voltage (V sub) application method for suppressing decay time, which modulates the V sub immediately after the removal of UV irradiation, which promotes injecting electrons from two-dimensional electron gas to the carbon-doped GaN (C-GaN) layer. The decay time was suppressed from 75 to 2 s. Moreover, the effectiveness of reset voltage application is confirmed by a demonstration that changes the UV intensity continuously.