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The first comparative study of dc, rf, and very high frequency (VHF) excitation for the plasma enhanced chemical vapor deposition of intrinsic layers of hydrogenated amorphous silicon (a-Si:H) is presented. The effects of hydrogen dilution on film stability are emphasized. Growth rates at comparable plasma power are presented for substrate temperatures between 100 and 300 °C and for various H2 dilution ratios. The optical band gap, H content, and electronic transport properties in the light-soaked state were measured. H2 dilution strongly reduces the growth rate for all techniques. The growth rate for the highest H2 dilution ratio is higher for VHF (∼4 A/s) than for dc (∼3 A/s) or rf (0.5–1 A/s) excitation. In all three cases, increasing the substrate temperature reduces the optical gap and the H content CH. Raising the substrate temperature slightly enhances stability. H2 dilution increases the optical gap for all three techniques. The H content of rf- and VHF-deposited samples increases with increasing ...

The missing correlation between film characteristics and a‐Si:H‐based p‐i‐n solar cells is still a controversial subject. The authors present a new parameter μ0τ0, evaluated from steady‐state transport measurements on a‐Si:H layers, which can indeed relate film quality and cell performance as far as the latter is limited by the quality of the intrinsic 〈i〉 layer. Thereby, two specific features of the evaluated μ0τ0 product can explain its successful role as a quality parameter for a‐Si:H: First, the computation of μ0τ0 takes into account the effects of the prevailing dangling bond occupation, which is very different in uniform films as compared to the occupation profile prevailing through the i layer of a p‐i‐n solar cell; second, the evaluated μ0τ0 product combines information about band mobility and defect density; furthermore it avoids some of the well‐known pitfalls of usual deep defect density measurements such as constant photocurrent method and photothermal deflection spectroscopy. Experimental dat...