Photoconductivity of iron doped amorphous carbon films on n-type silicon substrates

Abstract

The Fe doped a-C films on n-type silicon substrates were deposited by pulse laser deposition. The Fe doped a-C films are p-type semiconductor and they are rich in sp2 (∼75%). I-V characteristics and photoconductivity of the structures were measured in the current in-plane geometry. The photoconductivity with magnitude of 170∼220 was observed under white light illumination with power of 20 mW/cm2 at room temperature. The photoconductivity is ascribed to the p-n junction formed between the p-type a-C: Fe film and the n-type Si substrate whose reverse-biased saturation current increases intensively under illumination.