Comparative study between MEE- and MBE-grown InSb-nanocrystals on Se-terminated GaAs(001)

The dependence of growth method on InSb nanocrystal formation on a Se-terminated GaAs(001) substrate at 200°C was investigated by using migration enhanced epitaxy (MEE) and conventional molecular beam epitaxy (MBE).The InSb grown by MEE exhibited petal-like-shaped crystal islands with an estimated density of about 1× 109 cm-2. The MBE-grown sample, on the other hand, exhibited almost square- or rectangular-shaped crystal islands, and their density was about 5 times higher than that for the MEE-grown one; this is related to the difference in surface diffusion length and/or surface-resident lifetime depending on the migrating species (In or Sb). The in situ core-level synchrotron radiation photoelectron spectra for these two samples show that the MBE-grown InSb nanocrystals are almost stoichiometric, unlike the MEE-grown ones.