  Studies of n-CdZnTe crystals (photoluminescence, extrinsic photoconductivity,
Hall effect, time-of-flight technique) have shown that the excess concentration
of vacancies of cadmium (Vcd) is the main reason of low, as a rule, values of
product of mobility to life time of holes (mhth). The reduction of the
concentration of cadmium vacancies (decreasing of the intensity of near 1eV
photoluminescence band and an intensity of the (0.9-1.3) eV extrinsic
photoconductivity band) by annealing of the crystals at 600 C results in
increasing of value of mhth.
  Influence of Zn on formation of the basic photoelectric properties of CdZnTe
crystals has been explained by "self-control" of a concentration of cadmium
vacancies Vcd due to addition of Zn results in formation of divacancies of
metal, which in part dissociate and provide a crystal with necessary quantity
of monovacancies for processes of complex formation. That makes process of
obtaining of semi-insulating CdZnTe crystals less dependent from pressure Pcd
in comparison with CdTe. However with the purpose of obtaining CdZnTe crystals
with high value of mhth (i.e. with small concentration of the free vacancies of
cadmium) it is necessary to control Pcd above the crystal at stages of its
growth and annealing.
