Effect of nitrogen pressure on the performance of a-C:N/p-Si photodetector prepared by pulsed laser deposition

Amorphous nitrogen doped nanostructured carbon a-C:N films were prepared on glass and silicon substrates by pulsed laser ablation of graphite target using Nd:YAG laser pulses at laser fluence of 11.1 J/cm(2). The effect of nitrogen gas pressure (2.5 x 10(-2)-7.5 x 10(-1)) mbar on the structural, optical and electrical properties of a-C:N thin films was investigated by using X-ray diffraction XRD, Scanning electron microscopy (SEM), energy dispersive x-ray EDX, Fourier transformation infrared spectroscopy FT-IR, Raman spectroscopy, UV-vis transmittance and Hall effect. The film prepared at higher nitrogen pressure exhibited maximum optical transmittance and the optical band gap decreasing from 2 to 1.75 eV as nitrogen pressure increases from 2.5 x 10(-2) to 7.5 x 10 (-1) mbar. Raman data confirms that the I-D/I-G ratio of a-C:N films increases as nitrogen pressure increase. Increases the nitrogen pressure leads to increasing the electron mobility and decreasing the electrical resistivity of deposited film. The electrical and photoresponse properties of a-C:N/Si heterojunction photodetectors was studied as function of nitrogen gas pressure. (C) 2017 Elsevier GmbH. All rights reserved.