| Popis: |
High-efficiency III-V solar cells on low-cost substrates such as steel, are limited because a) the overlying III-V semiconductor stack gets contaminated with iron, b) it is not easy to deposit crystalline Ge thin-films on amorphous steel substrates. In this work, we report a TiN-based barrier layer that inhibits Fe diffusion into the overlying semiconductor. We also report a method to deposit crystalline germanium thin-film on steel on which high quality III-V layers can be deposited using laser annealing. PECVD amorphous germanium films were irradiated with a 532 nm laser with a fluence of 4 - 8 x 108 Jcm-2 which melted and re-crystallized the irradiated amorphous film into nano-crystalline germanium film. The recrystallized films were characterized using SEM and Raman spectroscopy. Films irradiated at higher fluence and films with higher thicknesses, had more crystalline order. The work enables future development of lost-cost GaAs solar cells. |
