Dependence of the optoelectronic properties of Se-doped silicon on the thickness of dopant film

Abstract

Se doped silicon is prepared by femtosecond-laser irradiation of Si coated with Si/Se bilayer films. The effects of Se film thickness on optical and electrical properties of Se doped silicon are studied. With the increase of the thickness of dopant film, the infrared absorptance increases significantly at wavelengths from 1100 to 2200 nm. At −10 V bias, the responsivities at 1064 nm for samples prepared with Se film thicknesses of 50, 75, 100 and 125 nm are 0.310, 0.786, 0.911 and 1.22 A/W, respectively. This investigation demonstrates that the increase of doping concentration is beneficial to improve infrared absorption and photoresponse of Se doped silicon. This observation has potential to improve the property of Se doped silicon and facilitate its application in photoelectric devices.