Growth and Characterization of GaAs Layers Grown on Ge/Si Substrates by Metalorganic Chemical Vapor Deposition

Epitaxial GaAs layers have been grown on (100) oriented Ge/Si substrates by metalorganic chemical vapor deposition. Double-crystal X-ray diffraction shows that the full width at half maximum of the (400) reflection obtained from 3 µm-thick GaAs is as small as 114 arc seconds. The GaAs surface dislocation density estimated by a molten KOH study is 4.9×10 6 cm -2 . Photoluminescence measurements show that an excitonic transition at 1.4852 eV dominates at 4.2 K. These results suggest that Ge/Si substrates are suitable for growing sufficiently high quality GaAs layers.