<title>Electrical compensation in CdTe and CdZnTe by intrinsic defects</title>

Abstract

The effects of two intrinsic deep levels on electrical compensation and effects of dislocations on carrier mobility in semi-insulating CdTe and CdZnTe radiation detector crystals are reported here. These levels were found in samples grown by conventional Bridgman and high-pressure Bridgman techniques. The levels were observed with thermoelectric effect spectroscopy at distinct temperatures corresponding to thermal ionization energies of Es1 equals 0.27 +/- 0.07 eV, Ed1 equals Ev + 0.735 +/- 0.005 eV and Ed2 equals Ev + 0.743 +/- 0.005 eV. The shallow level (Es1) is associated with dislocations. The first deep level (Ed1) is associated with the doubly ionized Cd vacancy acceptor and the second deep level (Ed2) is associated with the Te-antisite (TeCd). The second deep level (TeCd) was found to electrically compensate the material to produce high resistivity CdTe and CdZnTe, provided that the Cd vacancy concentration is sufficiently reduced during crystal growth or by post-growth thermal processing. The dislocations were found to affect the mobility of the carriers in the CdTe and CdZnTe crystals.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.