Spectroscopic evidence and control of compensating native defects in doped ZnSe

Electron paramagnetic resonance spectroscopy combined with photoexcitation is used to identify and characterise the defects responsible for the compensation in iodine or aluminium doped ZnSe bulk crystals. The principal g-values of the AlZnVZn complex are reported for the first time. The acceptor levels of both A-centres observed are determined at 0.50 and 0.54 eV above the valence band edge for ISeVZn and AlZnVZn, respectively. Annealing of these samples in Zn vapour is shown to be suitable for reproducible adjustments of the electron concentration at room temperature up to a few 1018 cm−3. The tight coupling of these vapour phase equilibrations with the electrical and spectroscopic analysis allows to propose a simple defect-chemical model.