Scanning tunneling miscroscopy study of InAs islands grown on GaAs(001) substrates

Scanning tunneling microscopy (STM) connected to molecular beam epitaxy (MBE) has been used to investigate InAs islands and wetting layers (WLs) on GaAs(001) substrates. STM results reveal that the size and density of InAs islands depend strongly both on the growth temperature and growth rate of InAs. With increasing the growth temperature, the island density becomes lower and the size larger. With increasing the growth rate, the island density becomes higher and the size smaller. Moreover, it is found that two-step growth by varying the growth temperature under a fixed growth rate results in the bimodal distribution of the InAs island-size. These results indicate that controlling the growth temperature and growth rate makes it possible to control the size distribution of InAs islands as well as the size and density of InAs islands.