The structural property of GaSb epilayers grown on semi-insulator GaAs (001) substrate by metalorganic chemical vapour deposition using Triethylgallium and trimethylantimony, was investigated by variation of the Sb:Ga ratio. An optimum Sb:Ga ratio of 1.4 was determined for these growth conditions. Using transmission electron microscopy, it was found that there was an interfacial misfit dislocations growth mode in this experiment, in which the large misfit strain between epilayer and substrate was relaxed by periodic 90deg. Interfacial misfit dislocations arrayed at the hetero-epitaxial interface. The rms roughness of a 300nm-thick GaSb layer was only 2.7nm in a 10μm x 10μm scan from atomic force microscopy result. The best hole density and mobility of 300nm GaSb epilayer were 5.27 x 106cm3 (1.20 x 106) and 553cm2/Vs (2340) at 77K from Hall measurement, respectively. These results indicated that the interfacial misfit dislocations growth mode could be used in MOCVD epitaxial technology similar to molecular beam epitaxy technology to produce the thinner GaSb layer with low density of dislocations and other defects on GaAs substrate for the application of devices.

High Hole Mobility of GaSb Relaxed Epilayer Grown on GaAs Substrate by MOCVD through Interfacial Misfit Dislocations Array. W.Zhou, X.Li, S.Xia, J.Yang, W.Tang, K.M.Lau: Journal of Materials Science & Technology, 2012,  28[2], 132-6