Wetting of Ga droplets in SiO$_2$/Si cavities: Application to self-assisted GaAs nanowire growth

TL;DR

This study analyzes how gallium droplets wet cylindrical and conical cavities in silicon dioxide to understand and control nanowire growth, providing insights into droplet behavior and wetting angles.

Contribution

It introduces a comparative analysis of surface energies for Ga droplets in different cavity geometries, aiding in controlling nanowire growth orientation.

Findings

Surface energy calculations for cylindrical cavities are explicit or numerical.

A relation between cavity geometry and wetting angles is established.

Results help improve vertical nanowire growth control.

Abstract

In this paper we compute and compare the surface energy of various Ga liquid droplets wetting a cylindrical cavity in various configurations. While for some of these configurations the surface energy can be computed explicitely for others numerical computation is needed. Motivated by the results obtained for the cylindrical cavities we explore the case of the more realistic situation, conical cavities. Our results provide a relation between the geometry of the conical cavity and the equilibirum wetting angles of the droplet on the bottom and on the sidewall of the cavity which insure the dewetting of the lateral surface. This is an important result toward the control of the verticality during the nanowire growth by the vapor liquid solid method.