Self-catalyzed growth mechanism of InAs nanowires and growth of InAs/GaSb heterostructured nanowires on Si substrates

Abstract

The growth mechanism of III–V nanowires (NWs) grown without the use of any foreign catalysts, especially the growth mechanism of InAs NWs grown on Si substrates, is still an open question and controversial. To make it clear, we in detail investigated metal–organic chemical vapor deposition (MOCVD) growth of InAs NWs on Si substrates. Based on assuming the growth of InAs NWs by self-catalyzed growth mode, we firstly realized the growth of InAs/GaSb heterostructured NWs both in the axial direction by utilizing the catalysis of In droplet and in the radial direction (core/shell structure) by consuming In droplet. In particular, we found the presence of a certain amount of In atoms in the top droplet of the InAs/GaSb axially heterostructured NWs, which is the direct evidence of self-catalyzed vapor–liquid–solid (VLS) growth mode for the growth of InAs NWs on Si. All the results obtained here support that the InAs NWs are grown by self-catalyzed VLS mechanism. The reasons for the absence of In droplets in the growth of InAs NWs were also discussed in details.