Optoelectronic Properties of CuInSe_2 Grown by Traveling Heater Method Using Cu-In Alloy Solvent

摘要

The CuInSe_2(CIS) crystals were grown by traveling heater method(THM) using Cu-40 at%In alloy as the solvent metal. The composition mapping by electron probe microscopic analysis was stoichiometric and homogeneous throughout the crystal. The conduction was p-type with the carrier concentration and hole mobility in the order of magnitude of 10~(20)-10~(22) m~3 and 10~(-3) m~2Vs~(-1) at 300 K, respectively. The emission peaks in the photoluminescence spectra were identified as the free exciton and the defects of Se vacancy(V_(Se)) and Cu antisite(Cu on In site, Cu_(In)). From the emission intensity measurement, it was found that the nonradiative recombination centers decreased in the direction from the bottom to the top end of the crystal, while the defects of V_(Se) and Cu_(In) remained almost uniform. The results indicate that the quality of the CIS crystal enhanced by the THM growth in comparison to that of the crystal by the Bridgman method in which non-radiative recombination centers were predominant.