DOMINANT DEFECT LEVELS IN DIAMOND THIN-FILMS - A PHOTOCURRENT AND ELECTRON-PARAMAGNETIC-RESONANCE STUDY

Characteristic features in photocurrent (PC) and electron paramagnetic resonance (EPR) spectra are discussed and attributed to main defects in the gap of optical-quality chemical vapor deposited diamond. A shou lder in the PC spectra with an onset at about 2.2 eV is attributed to the single-substitutional nitrogen defect (EPR P1 resonance at g = 2.0 024). A second feature in the PC spectra with an onset of about 1.3 eV is observed on ''as-grown'' samples with a hydrogen terminated surfac e. The defect level associated with this feature is hydrogen related, and this defect disappears after oxidation of the diamond sample surfa ce. The EPR g = 2.0028, which was also suggested to be H-related, is d iscussed. (C) 1998 American Institute of Physics. [S0003-6951(98)01525 -3].