GROWTH OF GERMANIUM-CARBON ALLOYS ON SILICON SUBSTRATES BY MOLECULAR-BEAM EPITAXY

Metastable Ge1-yCy alloys were grown by molecular beam epitaxy as homogeneous solid solutions having a diamond lattice structure. The substrates were (100) oriented Si wafers and the growth temperature was 600 degrees C. We report on measurements of the composition, structure, lattice constant, and optical absorption of the alloy layers. In thick relaxed layers, C atomic fractions up to 0.03 were obtained with a corresponding band gap of 0.875 eV. These alloys offer new opportunities for fundamental studies, and for the development of silicon-based heterostructure devices. (C) 1995 American Institute of Physics.