Size effects of nano-pattern in Si(1 1 1) substrate on the selective growth behavior of GaN nanowires by MOCVD

We report on the size effects of nano-patterned Si(1 1 1) substrates on the selective growth of GaN nanowires (NWs) using metal organic chemical vapor deposition. The nano-patterns on Si(1 1 1) substrates were fabricated by etching process of Au nano-droplets. The size of nano-patterns fabricated on Si(1 1 1) substrates were corresponding to size of Au nano-droplets, and the diameter of GaN NWs grown on nano-patterns was similar to the size of nano-pattern. Dense and well-oriented GaN NWs were grown on Si(1 1 1) substrates corresponding to the nano-patterns with an average diameter of about 50 nm. However, only a few GaN bulk grains, and mixed phase of a few NWs and bulk crystal of GaN were grown on the nano-patterned Si(1 1 1) having too small and large diameter, respectively, compare to the nano-patterns with diameter of 50 nm. Our results suggested that the selective growth of GaN NWs is strongly affected by the size of nano-patterns and its related mechanism.

Graphical abstractSchematic illustration showing the size effects of nano-pattern in Si(1 1 1) substrates on the selective growth of GaN nanowires (NWs) by using metal organic chemical vapor deposition (MOCVD).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Selective area growth of GaN nanowires (NWs) on a nano-patterned Si(1 1 1) substrate by MOCVD. ► Influence of the nano-patterns size on the formation of GaN NWs was investigated. ► The nano-patterns were fabricated by the oxidation of Si and the etching process of Au nano-droplets. ► The morphological and optical characteristics of the grown GaN NWs were investigated.