Effect of substrate orientation on the properties of the Si/PbS heterojunction

Abstract

The effect of the silicon substrate orientation on the structural and interface properties of the Si/PbS heterojunction has been found to be substantial. In the case of Si (100) substrates the PbS film shows a preferred orientation in the [100] direction and a grain size of approximately 3500 Å. For Si (111) substrates two preferred PbS orientations are found in the [220] and [311] directions. Calculations based on an interface bonding model indicate that the magnitude and polarity of the interface charge density are dependent on the silicon orientation. The bonding model in the case of the exact lattice match suggests that the presence of oxygen at the interface is the result of interaction with silicon dangling bonds. This conclusion is supported by Auger measurements of the interface oxygen concentrations as a function of silicon orientation.