High Responsivity, Low Dark Current Ultraviolet Photodetectors Based on Two-Dimensional Electron Gas Interdigitated Transducers

• DOI: 10.1021/acsphotonics.8b01169
• Publication Date: 2018-10-01T23:50:32Z
• Authors: Peter F. Satterth...; Ananth Saran Yala...; Noah A. Scandrette; A. K. M. Newaz; Debbie G. Senesky
• Keywords: Photocurrent; Ultraviolet; Photoconductivity

An ultraviolet (UV) photodetector employing the two-dimensional electron gas (2DEG) formed at AlGaN/GaN interface as an interdigitated transducer (IDT) is characterized under optical stimulus. The 2DEG-IDT exhibits a record high normalized photocurrent-to-dark current ratio of 6 × 1014. We also observe responsivity (7800 A/W) and ultraviolet–visible rejection (106), among highest reported values for any GaN architecture. argue that valence band offset in heterostructure essential achieving this responsivity, allowing large gains without necessitating presence trap states. Our proposed gain mechanism consistent with measurements scaling device channel width incident power. architecture has simple two-step fabrication process, compatible mobility transistor (HEMT) processing. This unique combination low dark current, attractive variety UV sensing applications.