Infrared response of Pt/Si/ErSi1.7 heterostructure: Tunable internal photoemission sensor

Abstract
We present the first internal photoemission response of a metal‐Si‐metal heterostructure. Using the Pt/Si/ErSi1.7 system, we show that the photoresponse of this new device can be strongly modified when a bias of a few hundred mV is applied between the two metallic electrodes: the cutoff wavelength is shifted from 1.4 μm to above 5 μm, and the quantum efficiency is increased up to 5% at 1.2 μm wavelength when a positive bias is applied to the front Pt electrode. These dramatic changes are attributed to a modulation of the effective potential barrier experienced by the photoexcited carriers when crossing the Si film.