Ultraviolet photodetectors and readout based on a‐IGZO semiconductor technology

• Published in: Journal of the Society for Information Display Vol. 31; no. 5; pp. 363 - 372
• Main Authors: Schellander, Yannick, Winter, Marius, Schamber, Maurice, Munkes, Fabian, Schalberger, Patrick, Kuebler, Harald, Pfau, Tilman, Fruehauf, Norbert
• Format: Journal Article
• Language: English
• Published: 01.05.2023
• Subjects: detection of ambient light; dual gate a‐IGZO thin‐film transistors; non‐visible spectrum optical sensing; operational amplifier; sensor integration; sensors under displays; switched capacitor; transimpedance amplifier; UV photosensors
• ISSN: 1071-0922; 1938-3657
• DOI: 10.1002/jsid.1202

In this work, real‐time ultraviolet photodetectors are realized through metal–semiconductor–metal (MSM) structures. Amorphous indium gallium zinc oxide (a‐IGZO) is used as semiconductor material and gold as metal electrodes. The readout of an individual sensor is implemented by a transimpedance amplifier (TIA) consisting of an all‐enhancement a‐IGZO thin‐film transistor (TFT) operational amplifier and a switched capacitor (SC) as feedback resistance. The photosensor and the transimpedance amplifier are both manufactured on glass substrates. The measured photosensor possesses a high responsivity R, a low response time tRES, and a good noise equivalent power value NEP. The combination of a real‐time ultraviolet photodetector and a readout circuit (transimpedance amplifier) manufactured on glass substrates based on amorphous indium gallium zinc oxide (a‐IGZO) semiconductor technology is shown. The presented photodetector uses a metal–semiconductor–metal structure and has a maximum responsivity of 120 A/W, a noise equivalent power of 0.2 nW/√Hz, and a response time of 30 ms.