The influence of growth conditions on the quality of CdZnTe single crystals

Experimental conditions were investigated for growth of inclusion-free near-stoichiometric CdZnTe single crystals with a minimized concentration of native point defects. The positions of the stoichiometric line P-S = 8 x 10(5) exp(- 1.76 x 10(4)/T) (atm) and the room-temperature and high-temperature pn lines were evaluated from high-temperature in situ galvanomagnetic measurements. The Cd pressure at the congruent melting point was estimated at similar to1.15-1.20 atm from analysis of the total inclusion volume of five single crystals fabricated at Cd pressures in the range of 1-1.3 atm. An inclusion-free single crystal was prepared at P-Cd similar to 1.2 atm. Calculations based on a model of two major defects, the Cd vacancy and the Cd interstitial, show that a very small deviation of PCd from P-S results in a large generation of the native defects. Thus a reproducible production of a high-resistivity material by a slow cooling along the P-S seems to be very difficult.