It was recalled that the defect density of plasma-deposited hydrogenated amorphous material was known to depend upon the thermal energy of growth precursors. The precursor temperature could be controlled independently of the substrate temperature by using a mesh-type electrode which was placed close to the substrate. Energized precursors had a higher surface diffusion coefficient, which resulted in a reduction of the steady-state defect density on the growth surface, and hence in the film bulk. The optical band gap and H content depended only upon the substrate temperature, while the defect density was sharply reduced with increasing mesh temperature. Amorphous hydrogenated material was prepared here which had a low defect density and a wide optical band gap.

G.Ganguly, H.Nishio, A.Matsuda: Applied Physics Letters, 1994, 64[26], 3581-4