Electrical and optical properties of sputtered amorphous silicon films prepared under a reduced pumping speed

Abstract
A series of amorphous silicon (a‐Si) films have been deposited by dc sputtering. We have found a new preparation parameter, namely, the pumping speed of the secondary vacuum pump which has a considerable influence on the electronic properties of the material. Samples deposited under a reduced pumping speed possess electrical properties which are extremely sensitive to the presence of hydrogen. Conductivity and photoconductivity may increase over several orders of magnitude with the addition of a relatively small amount of hydrogen.