A Raman Scattering, Ion Channelling and Photoluminescence Study of Argon Ion Radiation Damage in Cu(Ga,In)Se2 - Dose Dependence and Dose Rate Effects

Abstract

AbstractThe ternary chalcopyrite semiconductor CuInSe2 and related ternary compounds are promising materials for the production of high-efficiency thin film solar cells. In this paper we study the dose dependence of ion radiation damage produced by 30 keV and 80 keV Ar ions in single crystals and polycrystalline films of Cu(In,Ga)Se 2 over a wide dose range from 1012 to 1017 cm-2, using Raman spectroscopy and ion channeling measurements. For the first time, we also report on the dose rate dependence with a variation of the beam current density in the range 0.44 to 44 µcm-2. Even for low damage levels no significant dependence of the defect concentration or damage mechanism on the dose rate could be observed. From phonon correlation length considerations we estimate defect densities. They are in agreement with ion channeling data obtained in the 1015 to 1016 dose range, where the breakdown of the lattice structure occurs. In this dose range, the defect density is close to the concentration of implanted atoms. We conclude, that this high impurity concentration is responsible for the amorphization.