Effect of Illumination Area on the Ultrafast Temporal Response of MSM GaN Photodiodes
Abstract
We investigate the influence of spatial illumination profiles on the temporal response of metal–semiconductor–metal (MSM) gallium nitride (GaN) photodiodes. Using both simulation and experimental measurements, we compare the response curves under two scenarios: illumination confined to the active area between electrodes and extended illumination beyond the contacts. The results show that limiting the beam illumination to the active region significantly sharpens the response, reducing the long decay tails associated with slow carrier drift from peripheral regions. The experimental data closely match simulation predictions, confirming that illumination geometry plays a critical role in optimizing photodiode performance for ultrafast detection applications.
Fields of Study & Subjects
GaN-based semiconductor devices and materials
Photocathodes and Microchannel Plates
Plasmonic and Surface Plasmon Research
Publication details
- Journal / source
- IEEE Transactions on Electron Devices
- Publisher
- Institute of Electrical and Electronics Engineers (IEEE)
- Volume
- 73
- Issue
- 2
- Pages
- 894–899
- Publication date
- 5 January 2026