Electrical and photoelectric properties of polycrystalline diamond films deposited from an abnormal glow discharge

Abstract

Electrical and photovoltaic properties of polycrystalline diamond films (PDF), deposited from the abnormal glow discharge were analysed. Features of charge carrier transfer in PDF are determined by continuous energy distribution in the band gap of defect states of different nature. Dominated n-type conductivity activation component of electrical conduction and photoconductivity is complemented by a hopping mechanism with the participation of states near the Fermi level with a density 5.6·1017–2.1·1021 eV−1 cm−3. Activation transfer is realized in the exchange of charge carriers between the allowed bands and donor levels with the activation energy 0.007-0.21 eV, which are sparsely populated and have wide variation in their parameters. Trapping centers and carriers recombination are heterogeneously distributed in grain boundaries. Under lighting, the state density increases 3-5 times and probable jump length decreases by 1-3 nm. Spectral distribution centers of photosensitivity are correlated with the distribution of deep-level defects, determining the absorption spectra.