Sputtering of copper indium gallium diselenide (CIGS) offers a potential route to highly-manufacturable thin film solar cells. Thin films of CIGS are deposited from a quaternary sputtering target, and their composition, structure, and device performance are compared to those of state-of-the-art evaporated CIGS. SEM and TEM analysis reveal that the sputtered films have a unique morphology - differing significantly from that of evaporated films - with small grains near the bottom contact that coalesce into larger grains as film growth progresses. We examine the temperature dependence of grain growth by depositing films while varying deposition temperature from 85-600 °C. Devices that employ sputtered CIGS films as the absorber are fabricated. Light IV curves are obtained, and conversion efficiency as high as 10.5% is observed. Quantum efficiency measurements indicate that the morphology may have a strong impact on device performance.
展开▼
