PHOTODETECTOR ALGAAS GAAS STRUCTURES FORMED ON SI SUBSTRATES BY COMBINING LIQUID-PHASE AND MOLECULAR-BEAM EPITAXY METHODS/

Liquid phase and molecular beam epitaxy methods were combined in fabri cation of AlGaAs/GaAs/Si heterostructures to be used for fast-response photodetectors with the mesa configuration. Transmission electron mic roscopy indicated that the surface density of dislocations in GaAs lay ers grown by molecular beam epitaxy on Si substrates reached 10(7)-10( 8) cm-2. Suppression of antiphase domains by epitaxy was observed at s ufficiently small thicknesses of a growing GaAs layer, which sometimes reached approximately 1000 angstrom. Microcathodoluminescence data in dicated that the liquid phase epitaxy stage could reduce to (2-3) X 10 (4) cm-2, the density of defects in the active regions of such heteros tructures.