The atmospheric pressure thermal decomposition of disilane to produce a Si:H films was studied between 450 and 520° C in a laminar flow reactor. The structural properties of the films exhibited a strong dependence not only on substrate temperature but also on reactor flow position. Films deposited at higher substrate temperatures had less dihydride bonding in the films while the monohydride bonding remained relatively constant. Despite a decrease in the total hydrogen content of the films as the deposition temperature increased from 450 to 500° C, the AM1 photoconductivity increased over an order of magnitude and the hole diffusion length of the films doubled. In addition to the changes in structural and electrical properties as a function of substrate temperature, variations in these properties were also observed as a function of flow position. At early flow positions the amount of dihydride bonding in the films was small and the AM1 photoconductivity and hole diffusion lengths of the films increased. The flow dependence of the film properties is explained by changes in the film precursors due to the evolution of the gas phase chemistry.