VIS-NIR-SWIR multicolor avalanche photodetector originating from quantum-confined Stark effect in Si/β-FeSi_2/Si structure

摘要

A Si n-i-p avalanche photodetector with embedded β-FeSi_2 nanocrystals was developed. The device showed an ultrabroadband photoresponse from the visible (400 nm) to short-wavelength infrared (1800nm) ranges. Specific detectivity at zero bias conditions reaches 2 × 10~9 cmHz~(1/2)/W at 1300 nm and 2 × 10~8 cmHz~(1/2)/W above 1400 nm at room temperature. Observed quantum-confined Stark effect together with avalanche multiplication resulted in a simultaneous two orders of magnitude increase in the photoresponse and spectral sensitivity expanding to 1800 nm when the device is operated in avalanche mode. The application fields of the proposed photodetector potentially include integrated Si photonics and multicolor photodetection; the quantum-confined Stark effect gives grounds for the development of fast-operated electro-optical modulators.