Piezoelectric Domains in the AlGaN Hexagonal Microrods: Effect of Crystal Orientations

TL;DR

This study investigates the piezoelectric properties and domain structures of AlGaN microrods grown on AlN/Si substrates, revealing how crystal orientation influences polarization and piezoelectric behavior in these nanostructures.

Contribution

It provides new insights into the piezoelectric domain behavior of AlGaN microrods and their dependence on crystal orientation, using advanced microscopy techniques.

Findings

Piezoelectric domains are influenced by microrod orientation.

The piezoelectric coefficient varies with crystal inclination.

High optical quality of AlGaN microrods confirmed.

Abstract

Presently, the piezoelectric materials are finding tremendous applications in the micro-mechanical actuators, sensors and self-powered devices. In this context, the studies pertaining to piezoelectric properties of materials in the different size ranges are very important for the scientific community. The III-nitrides are exceptionally important, not only for optoelectronic but also for their piezoelectric applications. In the present study, we synthesized AlGaN via self catalytic vapor-solid mechanism by atmospheric pressure chemical vapor deposition technique on AlN base layer over intrinsic Si(100) substrate. The growth process is substantiated using X-ray diffraction and X-ray photoelectron spectroscopy. The Raman and photoluminescence study reveal the formation of AlGaN microrods in the wurtzite phase and ensures the high optical quality of the crystalline material. The single crystalline, direct wide band gap and hexagonally shaped AlGaN microrods are studied for understanding the behavior of the crystallites under the application of constant external electric field using the piezoresponse force microscopy. The present study is mainly focused on understanding the behavior of induced polarization for the determination of piezoelectric coefficient of AlGaN microrod along the c-axis and imaging of piezoelectric domains in the sample originating because of the angular inclination of AlGaN microrods with respect to its AlN base layers.