Positron annihilation lifetime (PAL) spectroscopy，photo-induced current transient spectroscopy (PICTS) and thermally stimulated current (TSC) have been employed to study the formation of compensation defects and their evolvement under iron phosphide (IP) ambience or pure phosphide (PP) ambience. In the formation of IP SI-InP, the diffusion of Fe atoms suppresses the formation of some open-volume defects. As to PP SI-InP, VInH4 complexes dissociate into acceptor vacancies VInHn(n-3)(n=0,1,2,3), which compensate residual donor type defects and make the sample semi-insulating. Electron irradiation-induced deep level defects have been studied by TSC in PP and IP SI-InP, respectively. In contrast to a high concentration of irradiation-induced defects in as-grown and PP annealed InP, IP SI-InP has a very low concentration of defects.

ositron lifetime spectroscopy (PAS) and Coincidence Doppler broadening measurements have been performed in as-grown and annealing single crystal ZnO. The temperature dependence observed in annealed ZnO indicates that the defect is removed during annealing. By combining the Doppler broadening measurements, we infer that there isn′t hydrogen filling the zinc vacancy site in the as-grown ZnO due to the same characteristics in CDB for as-grown and annealed ZnO samples

In order to get solar grade silicon, large cold crucible has been used in an induction heat furnace. By controlling the relative location of the crucible and coils, directional solidification was realized. More than 200 kg multi-crystalline silicon ingot was produced in a batch with short work time. The removal rate of most metal impurities was high, typically higher than 99% for transition metals like iron. Non-metallic elements such as boron and phosphorus could not be removed efficiently because of larger equilibrium segregation coefficient. The concentration of phosphorus was one third of the feedstock due to the vaporization in the melting process. The distribution of impurities agreed with the solidification principle. Quartzes and carbon was not used, which ensured silicon prevent from the contamination. Cooperated with other methods, large scale of solar grade silicon was produced.