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Hydrogenated nanocrystalline silicon thin films were deposited at a high rate of 0.8 nm s−1 by conventional (13.56 MHz) plasma enhanced chemical vapour deposition from SHi4/H2 gas mixture at a low temperature of 200 °C. The effects of hydrogen dilution, radio frequency power density, substrate temperature and deposition pressure on the crystalline volume fraction and the deposition rate of films were systematically investigated. The results show that the high hydrogen dilution and the substrate temperature are favourable for improving the crystallinity properties. The high deposition rate requires high power density over 0.7 W cm−2 in combination with high deposition pressure above several hundreds of Pa to overcome the degradation of film quality.

This paper describes the role of Ge as an enabler for light emitters on a Si platform. In spite of the large lattice mismatch of ~4.2% between Ge and Si, high-quality Ge layers can be epitaxially grown on Si by ultrahigh-vacuum chemical vapor deposition. Applications of the Ge layers to near-infrared light emitters with various structures are reviewed, including the tensile-strained Ge epilayer, the Ge epilayer with a delta-doping SiGe layer, and the Ge/SiGe multiple quantum wells on Si. The fundamentals of photoluminescence physics in the different Ge structures are discussed briefly.