Growth Temperature Dependence of InAs Islands Grown on GaAs (001) Substrates

Abstract

Scanning tunneling microscopy (STM) in conjunction with molecular beam epitaxy has been used to investigate InAs islands and wetting layers on GaAs(001) substrates. STM results reveal that the size, density and shape of InAs islands strongly depend on the growth temperature of InAs. With increasing the growth temperature, the island density decreases, the size increases, and the shape becomes round rather than elliptical. In the photoluminescence (PL) results, a PL peak shift is observed with increasing InAs growth temperature. This shift agrees with the STM observation that larger islands are grown at higher growth temperatures. The change in the size and density of islands can be explained in terms of a critical nucleus in heterogeneous nucleation. These results indicate that controlling the growth temperature makes it possible to control the size, density and shape of InAs islands.