Initial Growth Processes of ZnSe on Cleaned GaAs(001) Surfaces by Metalorganic Vapor Phase Epitaxy

The effect of organic As flow during the thermal cleaning of GaAs substrates in metalorganic vapor phase epitaxy (MOVPE) and the initial growth of ZnSe on the cleaned GaAs surfaces are investigated using atomic force microscopy, X-ray diffraction and photoluminescence measurements. The thermal cleaning with organic As flow in MOVPE is effective to form atomically flat GaAs surfaces and to grow high-quality ZnSe films. The initial growth processes of ZnSe films are critically dependent on the GaAs surface and on the VI/II flow ratio for the ZnSe growth. The initial growth process of ZnSe films on GaAs surfaces is dominated by the two-dimensional growth mode for Zn-rich growth conditions, while three-dimensional island growth becomes dominant as the Se flow rate increases.