a-Si:H prepared by low-energy ion beam assisted reactive evaporation

Abstract

a-Si:H has been deposited using low-energy (~55 eV) ion beam assisted reactive evaporation. An ion beam formed in an ion source using silane as the feed-through gas is directed at the substrate during film deposition. For this a-Si:H deposited on substrates held at temperatures above 490 K, the resulting films have only the silicon monohydride bonding configuration observable by IR absorption. Small amounts of the silicon dihydride or polyhydride configurations may be present in samples made on substrates held near 395 K. Electrical conductivity, optical band gap and the total hydrogen concentration all exhibit a reduced dependence on the substrate temperature relative to that observed in samples made without the use of the ion beam. Dark to light (AM1) conductivity ratios typically exceed 103.