Abstract: A quantity of silicon serving as a source of the element silicon for use in a molecular beam epitaxial growth apparatus where the silicon is in the form of a monocrystalline wafer with a plurality of electrically parallel filaments separated by slots that pass completely through the wafer, each filament having a length dimension that is greater than the width and height dimensions, joined at a broad contact area at each filament end and where an electric current is passed through the filaments through the broad contact areas.

Abstract: When growing GaAs by molecular beam epitaxy (MBE), a typical related reaction acts to affix Ga.sub.2 O.sub.3 to the growth surface and hence incorporates such oxide contaminants in the epitaxial layer as it is grown. Such contaminants may yield crystals of poor electrical and optical properties. When Al is added to the Ga source crucible, the Ga.sub.2 O flux is reduced substantially thereby suppressing the formation of such oxide contaminants and remove a serious constraint to MBE growth. When doping GaAs with Mg to form a p-type GaAs layer, unity Mg doping efficiency is achieved by including 0.1% Al in the Ga effusion cell. Such an inclusion of Al improves the Mg doping efficiency by suppressing the formation of MgO, and allows MBE growth at lower substrate temperatures and at higher growth rates.