Effect of in-plane alignment on selective area grown homo-epitaxial nanowires

In-plane selective area growth (SAG) of III-V nanowires (NWs) has emerged as a scalable materials platform for quantum electronics and photonics applications. Most applications impose strict requirements on the material characteristics which makes optimization of the crystal quality vital. Alignment of in-plane SAG NWs with respect to the substrate symmetry is of importance due to the large substrate-NW interface as well as to obtain nanostructures with well-defined facets. Understanding the role of mis-orientation is thus important for designing devices and interpretation of electrical performance of devices. Here we study the effect of mis-orientation on morphology of selectively grown NWs oriented along the [1 (1) over bar (1) over bar] direction on GaAs(2 1 1) B. Atomic force microscopy is performed to extract facet roughness as a measure of structural quality. Further, we evaluate the dependence of material incorporation in NWs on the orientation and present the facet evolution in between two high symmetry in-plane orientations. By investigating the length dependence of NW morphology, we find that the morphology of approximate to 1 mu m long nominally aligned NWs remains unaffected by the unintentional misalignment associated with the processing and alignment of the sample under study. Finally, we show that using Sb as a surfactant during growth improves root-mean-square facet roughness for large misalignment but does not lower it for nominally aligned NWs.

Automated summary

In-plane selective area growth of III-V nanowires is important for quantum electronics and photonics applications, but crystal quality optimization is vital. Understanding the role of mis-orientation is important for device design and interpretation of electrical performance. This study investigates the effect of mis-orientation on morphology and material incorporation in selectively grown NWs and shows that using Sb as a surfactant during growth can improve surface roughness for large misalignment.