Preparation of a-SiC:H/a-GeC:H superlattices by dual magnetron sputtering

Abstract

Amorphous semiconductor superlattices composed of hydrogenated amorphous silicon carbon alloys and germanium carbon alloys have been prepared by a dual magnetron sputtering method. A small-angle x-ray diffraction measurement has indicated that the superlattices consist of well-defined smooth layers. Optical band gap has been examined for a series of samples; the thickness of the germanium carbon layer was changed from 20 to 130 Å, while the thickness of the silicon carbon layer was kept constant at 60 Å. The optical band gap increases upon decreasing the thickness of the germanium carbon layer, indicating quantum size effects due to the formation of superlattice structures.