Characterization of high-resistivity poly-CdZnTe thick films grown by thermal evaporation method

The high-resistivity polycrystalline CdZnTe thick films are grown by thermal evaporation method. The electrical properties of polycrystalline CdZnTe having high resistivity were investigated using time of flight technique. We have measured the average drift mobility and mobility lifetime of polycrystalline CdZnTe. In the comparison of annealed samples at different conditions, the variation of resistivity in the polycrystalline CdZnTe is considered to be related to the fluctuation of carrier concentration. From the analysis of transient photocurrent of time of flight based on multiple trapping model, we have found that the two dominant localized states which is considered to be related to the Cd vacancy (E_V+0.36 eV), and grain boundary defects (E_V+0.75 eV) play a dominant role in increasing resistivity through compensation process.