High quality InAs and GaSb thin layers grown on Si (1 1 1)

Abstract

We have investigated growth of thin epitaxial layers of InAs on Si (1 1 1) substrates by metalorganic vapor phase epitaxy (MOVPE) and successfully grown GaSb layers on InAs. Furthermore, we have studied the effect of growth temperature and material flow on the nucleation stage and also nucleated GaSb nanowires on the underlying GaSb layer. The InAs layers are grown by a standard two-step growth approach. The main parameter under investigation is the effect of incorporating more nucleation layers into the growth process. The addition of more nucleation layers clearly correlates with the surface morphology and quality of the resulting InAs layer. Morphological and structural characterizations prove that a perfect quality InAs layer is achieved by incorporating 4 nucleation layers. Deposited layers with 250 nm thickness and 0.4 nm atomic step roughness have a mobility of 2400 cm 2/Vs and a carrier concentration of 2.7×10 18 cm −3. Moreover, we have utilized the InAs film to grow a GaSb layer and observed atomic step roughness for a thin film of ∼300 nm. Finally we demonstrate the growth of GaSb nanowires on the GaSb layer.