Electrical properties of Si 1−x−y Ge x C y and Ge 1−y C y alloys

The effects of carbon on the structural and electrical properties of Si1−x−yGexCy and Ge1−yCy alloys grown by the molecular beam epitaxy have been examined by Hall effect measurements, current-voltage measurements, x-ray diffraction, and atomic force microscopy. Hall effect measurements showed that the addition of carbon increased the hole mobility in GeC compared to pure Ge, we attributed this increase to improved crystalline quality and reduced surface roughness. Current-voltage characteristics of SiGeC/Si and GeC/Si heterojunction diodes showed that with increasing carbon, the reverse leakage current decreased and the forward turn-on voltage increased, attributed to the increase in bandgap energy and reduction of intrinsic carrier concentration ni.