Metal-semiconductor-metal structured p-i-n GaN/AlGaN ultrafast detectors for deep-UV photodetection

S. F. Nwabunwanne; W. R. Donaldson

doi:10.1117/12.2648448

15 March 2023 Metal-semiconductor-metal structured p-i-n GaN/AlGaN ultrafast detectors for deep-UV photodetection

S. F. Nwabunwanne, W. R. Donaldson

Proceedings Volume 12421, Gallium Nitride Materials and Devices XVIII; 124210O (2023) https://doi.org/10.1117/12.2648448
Event: SPIE OPTO, 2023, San Francisco, California, United States

Conference Poster

Abstract

We report the productive outcome of the design, fabrication, and testing of a new class of GaN/AlGaN-based ultrafast, sensitive photodiodes for deep-UV solar blind photodetection. Pt was employed as the interdigitated metal electrode to establish that while a Schottky contact was formed at the metal/semiconductor heterojunction, it was the quantum wells in the p-i-n vertical structure that produced the diode characteristics of the detectors. The metal‒semiconductor‒metal design retained its ultrafast property as expected in the p-i-n structure because the spacing between the interdigitated fingers was asymmetrically implemented to optimize the photogenerated carriers’ transit time from the quantum well to the external circuitry. Also, the vertical p-i-n structure provided its renowned efficient photocarrier generation, which was significantly enhanced by the delta quantum well architecture of the vertical epitaxial structure. The active area of the device was 300 μm × 300 μm with 5-μm finger width, and asymmetric electrode spacing of 2 μm, 3 μm, and 5 μm. The best device had peak responsivity of 3.5 A/W under 262-nm illumination with full width half maximum of 337.2-ps and 37.5-ps rise times when biased with 20 V.

Citation Download Citation

S. F. Nwabunwanne and W. R. Donaldson "Metal-semiconductor-metal structured p-i-n GaN/AlGaN ultrafast detectors for deep-UV photodetection", Proc. SPIE 12421, Gallium Nitride Materials and Devices XVIII, 124210O (15 March 2023); https://doi.org/10.1117/12.2648448

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