Amorphous and micro-crystalline silicon for photovoltaic application

Theauthors have investigated the influence of anneal treatment on hydrogenated amorphous silicon films. The a-Si:H was deposited on metal substrates. Structures investigated were i/n⁺/Mo, n/n⁺ /Mo, p/p⁺/Mo, and PIN/n⁺/S.S. Four types of thermal annealing were done; nitrogen atmosphere, vacuum, rapid thermal anneal (RTA), and excimer laser anneal. The anneal temperature ranged from 100 to 1200°C. Dark and light I-V studies show an improvement in short circuit current and open circuit voltage with a low temperature anneal (200-300°C). Raman scattering spectroscopy examination showed that a microcrystallization initiated even at a low temperature of 600°C. The authors found that anneal time has only a small effect on crystallization but that the anneal temperature has a critical effect. The microcrystalline silicon exhibited improved photo response after RF plasma hydrogen passivation of grain boundaries