Cu(InGa)Se$_2$ 박막의 성장온도에 따른 태양전지의 광전특성 분석

Photovoltaic Properties of Solar Cells with Deposition Temperature of Cu(InGa)Se$_2$ Films

The substrate temperature is an important parameter in thin film deposition process. In this paper the effects of the substrate temperature on the properties of CuIn0.75Ga0.25Se2(CIGS) thin films are reported. Structure, surface morphology and optical properties of CIGS thin films deposited at various substrate temperatures have been investigated using a number of analysis techniques. X-ray diffraction (XRD) analysis shows that CIGS films exhibit a strong <112> preferred orientation. As expected, at higher substrate temperatures the films displayed a higher degree of crystallinity. The <112> peak was also enhanced and other CIGS peaks appeared simultaneously These results were supported by experimental work using Raman spectroscopy. The Raman spectra of the as-grown CIGS thin films show only the Al mode peak. The intensity of this peak was enhanced at higher deposition temperatures. Scanning electron microscopy (SEM) results revealed very small grains in films fabricated at 48$0^{\circ}C$ substrate temperature. When the substrate temperature was increased the average grain size also increased together with a reduction in the number and size of the voids. The deposition temperature also had a significant influence on the transmission spectra.