GaN metal-insulator-semiconductor ultraviolet (UV) photodetectors (PDs) with silver (Ag) nanoislands on a silicon dioxide (SiO2) gate layer were fabricated and characterized. Samples with different Ag mass thickness values were prepared on SiO2/sapphire template substrates and characterized by transmission spectral to confirm the surface plasmon resonance (SPR) effect. By examining the transmission spectra of Ag nanoislands on the SiO2/sapphire substrates, two transmission dips were observed in each spectrum. The transmission dip in the blue region was more significant than that in the UV region, but visible light with photon energy less than the bandgap of GaN was not absorbed to generate significant response. By introducing the Ag nanoislands, the UV-to-visible rejection ratio (RUV/vis) of spectral responsivity was at least ten times higher than those of PDs without Ag nanoislands. The RUV/vis enhancement was mainly due to the increase in UV response caused by SPR at approximately 360 nm induced by Ag nanoislands to enhance UV-light absorption.
|Journal||IEEE Journal on Selected Topics in Quantum Electronics|
|Publication status||Published - 2014 Nov 1|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering