Structural and electronic differences between deuterated and hydrogenated amorphous silicon

Both as-deposited and plasma-treated hydrogenated and deuterated amorphous silicon (a-Si:H and a-Si:D) films are prepared by plasma-enhanced chemical vapor deposition. Their structural and electronic characteristics are studied and compared. It is found that the deuterium concentration of a-Si:D is higher than the hydrogen concentration of a-Si:H in as-deposited samples, but is less in plasma-treated samples, which is consistent with the photoluminescence spectra. Besides, the proportionality constants relating the integrated stretching mode absorption to the concentrations of Si-D and Si-H bonds were determined, i.e., 1 × 10²⁰ for Si-D and 6.9 × 10¹⁹ for Si-H, by means of secondary ion mass spectrometry.