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

Metastable Ge1-yCy alloys were grown by molecular beam epitaxy as homo geneous solid solutions having a diamond lattice structure. The substr ates were (100) oriented Si wafers and the growth temperature was 600 degrees C. We report on measurements of the composition, structure, la ttice constant, and optical absorption of the alloy layers. In thick r elaxed layers, C atomic fractions up to 0.03 were obtained with a corr esponding band gap of 0.875 eV. These alloys offer new opportunities f or fundamental studies, and for the development of silicon-based heter ostructure devices. (C) 1995 American Institute of Physics.