Compensation of CdTe by doping with gallium

Semi-insulating CdTe single crystals doped with Ga were grown from the vapo ur phase by the modified Markov technique MMT. The study of the resistivity map in the cross-sections cut along the growth direction has been performe d. The compensation phenomenon is analysed in the framework of the three le vels Fermi-statistic model. It is shown that a semi-insulation behaviour th roughout the ingot is due to the compensation of shallow impurities by the deep level. From the low-temperature photoluminescence spectra it was concl uded that shallow donors (Gac) are partly compensated by (Ga-Cd-V-Cd)(-) an d (Ga-Cd-Cd-Tc) complexes and by residual acceptors (Na-Cd, Cu-Cd). The mic roscopic structure of (Ga-Cd-Cd-Tc)) complex is proposed based on the value of its local phonon mode and the growth conditions. A native defect like T e-Cd which has a deep level near the middle-band-gap is suppose to dive a s table compensation and a tolerance for variation in shallow impurity concen trations.