Control of Defects in CuInS2Thin Films by Incorporation of Na and O

We investigated the effects of the incorporation of both Na and O on defect structures for p-type Cu-poor CuInS2thin films on the basis of the analysis of experimental data using photoluminescence and the secondary ion mass spectrometry and theoretical results obtained by ab-initioelectronic band structure calculations. We propose a model of the defect structure for CuInS2codoped with Na and O. The NaCuand OSform a complex in which they occupy nearest-neighbor sites. The above complex plays an important role in the annihilation of the deep level due to the n-type divacancy which includes Cu vacancies (VCu) and vacancies of the sulfur close to the VCusite.