Production and characterization of germanium solar cells and germanium thin films for photovoltaic applications

This work aims preparation of Ge solar cells used as substrates for III-V multi-junction solar cells by forming the p-n junction through ion implantation. Ge was doped with different P concentrations in order to achieve maximum efficiency for solar cells. The influence of 31P+ concentration, annealing temperatures and annealing times on the I-V curves of the Ge solar cells were investigated. Solar cells parameters Isc and Voc values are increased with increasing 31P+ concentration in different concentration implanted Ge solar cells. Best results were obtained in the I-V measurement from the sample annealed at 650 oC for 120 s depending on the annealing temperatures. Besides for photovoltaic applications structural, properties of poly-crystalline Ge thin films deposited on different substrates were investigated as a function of annealing temperatures through Raman and XRD measurements. Crystallization of Ge thin films deposited on different substrates is increased with increasing annealing temperatures. The crystallization is observed at annealing temperatures of 300 oC for 60 minutes in the metal induced crystallization.