Intrinsic or lightly boron‐doped amorphous silicon films were produced by chemical vapor deposition (CVD) from disilane at temperatures from 380 to 460 °C and at growth rates from 0.1 to 40 A˚/s. The density of states (DOS) near the middle of the mobility gap was determined by space‐charge‐limited conduction onn‐i‐nstructures and by steady‐state capacitance‐temperature spectroscopy onp‐i‐nstructures. Very close agreement was found between the two techniques for intrinsic layers deposited under similar conditions. The DOS distribution is rather flat from 0.60 to 0.75 eV from the conduction‐band edge and has a range of 1–6×1017cm−3 eV−1for intrinsic films, with the minimum occurring for depositions at 440 °C independent of growth rate or contaminants in the disilane. Diborane levels from 9 to 18 ppm in the gas phase reduces the DOS at 440 °C to 3–6×1016cm−3 eV−1. The exponential absorption below the band edge in the range 1.4–1.6 eV was determined from primary photocurrent spectra ofp‐i‐nstructures. The Urbach edge parameterE0ranged from 0.048 to 0.056 eV with the minimum also occurring for depositions at 440 °C, independent of growth rate and boron content. Comparison to glow‐dischargea‐Si:H films indicates that CVDa‐Si:H films have a similar amount of structural disorder, determined fromE0, but an inherently larger DOS deep in the gap. A model is proposed in which boron reduces the high midgap dangling bond density caused by insufficient weakly bonded hydrogen in the film as a consequence of the high deposition temperatures. The model is consistent with other measurements, such as hole collection width.