Spectrally selective photodetection in the near-infrared with a gold grating-based hot electron structure
Hongbin Xiao, Shu-Cheng Lo, Yi-Hsin Tai, Ya‐Lun Ho, J. Kenji Clark, Pei‐Kuen Wei, Jean‐Jacques Delaunay
Abstract
A Si channel-separated interdigitated Au grating structure is demonstrated to achieve spectrally selective photodetection in the C-band (1530–1565 nm) in this work. The measured full width at half-maximum of the structure reaches as narrow as 23 nm, and the measured responsivity reaches 804 nA/mW at the resonant wavelength of 1550 nm and the bias voltage of 0.08 V. The responsivity represents a large variation of 59% when the light wavelength is varied by only 20 nm (from 1550 to 1530 nm). A theoretical model is also performed to quantify the photocurrent response in terms of the optical and electrical properties of the structure. The strongly resonant and narrowband photocurrent response and readily tunable resonant wavelength not only enable the structure to achieve spectrally selective photodetection in the near-infrared region but also make it amenable to the application of sensing devices, imaging devices, and other optoelectronic devices working in the sub-bandgap regime of semiconductor materials.