The Co-film-thickness dependent lateral photoeffect in Co-SiO2-Si metal-oxide-semiconductor structures

We report a transient lateral photoeffect (LPE) in thin metallic Co films deposited on n-type Si substrates with native SiO2 surfaces. Under the nonuniform irradiation of a laser beam, the lateral phtovoltage (LPV) shows high sensitivity to the laser position in the metal film plane. This effect can be interpreted by the metal-semiconductor (MS) junction formed between metal and semiconductor. The LPV depends significantly on the thickness of Co film. The position sensitivity shows a peak value of 42.6 mV/mm for Co-2.8 nm-SiO2-Si and decreases greatly with the increase of the Co film thickness. We explain that by the shorting effect of the metallic film. (C) 2008 Optical Society of America.