Photoluminescence study of high energy proton irradiation on Cu(In,Ga)Se2 thin films

Publication date: 31 March 2016
Source:Thin Solid Films, Volume 603
Author(s): Bonhyeong Koo, June Hyuk Lee, Donghyeop Shin, Byung Tae Ahn, Byungha Shin
We have studied the effect of proton irradiation on Cu(In,Ga)Se2 (CIGS) thin films using photoluminescence (PL). We used a 10MeV proton beam with varying doses from 10⁹ to 10¹² cm⁻². Intensity-dependent low temperature PL measurements suggest that the proton irradiation does not create a new defect level but instead changes the number of preexisting defects in the detection range of the PL system. By comparing PL spectra after the proton irradiation with those obtained after thermal annealing under inert gas as well as under hydrogen gas ambient, we find that the irradiation-induced change in the defect structure does not originate from the incorporation of hydrogen but from energetics of the irradiating particles. Electrical resistivity of the proton irradiated CIGS thin films is shown to decrease after the proton irradiation, and this is explained by the reduction of the concentration of compensating donor-like defects, specifically selenium vacancies, based on the PL results.