Fourier-transform photo-current spectroscopy was used for the first time to study defects in nominally undoped chemical vapour deposited diamond layers. The hydrogenated surface of diamond (as-grown or post-hydrogenated) was annealed in air and changes in surface conductivity and photoconductivity were monitored as a function of temperature and time. The reduction in surface conductivity with annealing led to an enhancement of photosensitivity and permitted the study of the spectral distribution of the photo-ionization cross section of shallow and deep defects in the gap over several orders of magnitude at 77 to 400K. The photo-Hall effect was used for the determination of the sign of the photo-generated carriers. An anomalous temperature dependence of the acceptor defect level was detected.

Fourier-Transform Photocurrent Spectroscopy of Defects in CVD Diamond Layers. R.Kravets, V.Ogorodniks, A.Poruba, P.Moravec, M.Nesladek, J.Rosa, M.Vanecek: Physica Status Solidi A, 2002, 193[3], 502-7