Abstract: A high quality non-single-crystal silicon alloy material including regions of intermediate range order (IRO) silicon alloy material up to but not including the volume percentage required to form a percolation path within the material. The remainder of the material being either amorphous or a mixture of amorphous and microcrystalline materials. The materials were prepared by CVD using differing amounts of hydrogen dilution to produce materials containing differing amounts of IRO material. Preferably the material includes at least 8 volume percent of IRO material.