Four wave mixing study on coalescence overgrowth of GaN nanocolumns on sapphire

TL;DR

This study investigates the coalescence overgrowth of GaN nanocolumns on sapphire using MOCVD, focusing on growth optimization, characterization, and the potential for dislocation reduction through lateral strain relaxation.

Contribution

It introduces a novel approach to coalescence overgrowth of GaN nanocolumns with optimized growth parameters and innovative characterization techniques.

Findings

Successful coalescence overgrowth of GaN nanocolumns demonstrated.

Potential for dislocation reduction via lateral strain relaxation.

Nanoimprint lithography used to pattern SiO2 layers with various hole sizes.

Abstract

Coalescence overgrowth of pattern-grown GaN nanocolumns (NC) on c-plane sapphire substrate with metal organic chemical vapour deposition is demonstrated. The subsequent coalescence overgrowth opens a possibility for dislocation reduction due to the lateral strain relaxation in columnar geometry. We present further growth optimization and innovative characterization of MOCVD layers, overgrown on the columnar structure with varying diameter of colums. Nanoimprint lithography was applied to open circular holes of 250, 300, 450, 600 nm in diameter on the SiO2 layer, deposited on the GaN layer on c-plane sapphire template.