Preparation and characteristics study of diamond like carbon/silicon heterojunction photodetector by pulsed laser deposition

Abstract

In this paper, amorphous undoped diamond-like carbon films were deposited on glass and silicon substrates by pulsed laser ablation of graphite target; using nanoseconds frequency doubled Nd: YAG laser pulses. The effect of laser fluence (9.5–14.3 J/cm2) on optical, structural, morphological, and electrical properties of diamond like carbon films was studied by X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, photoluminescence, and UV–Vis transmittance. UV–Vis results revealed a decreased indirect optical band gap from 2.2 to 1.92 eV with increasing laser fluence from 9.5 to 14.3 J/cm2 leads. The ID/IG ratio and sp2 bonded percentage of DLC films increased with laser fluence increase. Films prepared at a higher laser fluence yield lower electrical resistivity. The dark and illuminated current–voltage characteristics at room temperature of diamond like carbon/Silicon heterojunction under the effect of laser flunce were examined and analyzed. Our results demonstrated an optimum photodetectors’ responsivity of 450 m AW−1 at 10 V bias.