Optical absorption in alloys of Si, Ge, C, and Sn

Abstract

Group IV semiconductor alloy systems offer promise as variable band gap alloys compatible with Si technology. Binary, ternary, and quaternary group IV alloys were grown by molecular beam epitaxy on Si substrates. The fundamental absorption edge was measured by Fourier transform infrared spectroscopy to obtain the optical band gap of the alloys, and the position of the fundamental absorption edge was observed to depend on the experimentally measured alloy composition. Our results indicate a variety of Si-rich group IV alloys with various band gaps are experimentally producible.