Type Conversion of Polycrystalline CdZnTe Thick Films by Multiple Compensation

Semi-insulating n-type polycrystalline CdZnTe thick films are deposited by thermal evaporation method. The solubility of Cl in CdZnTe limits high doping concentration that establish full compensation. To make the most use of merit of Cl, heavy metals (Pb, Sn) are co-doped in CdZnTe. The electrical and optical properties of Pb and Sn co-doped with Cl are characterized by IV, PL and TOF measurement. Depends on the doping concentration of Pb or Sn, there was drastic changes in resistivity and conductivity type. In semi-insulating polycrystalline CdZnTe thick films, the A-center level that is found in compensated material, did not found. The electron mobility is about 88 cm²/Vs and for the first time the gamma ray spectrum of ²⁴¹Am was detected using polycrystalline CdZnTe thick films.