Available student project - GeSn defect properties measured by nanoindentation

Research fields

Project details

This project is focussed on materials that can improve optoelectronic detector development. Remote plasma enhanced chemical vapor deposition (RPECVD) is a useful method for growing alloy films. We have used RPECVD to grow GeSn films on Si substrate with a range of Sn compositions and with thicknesses ranging from up to a few microns. Threading defects within the GeSn alloy exhibit varying characteristics at different depths, which are more notably at the interface due to crystal lattice mismatches. Understanding these defects is essential for improving growth processes and fabricating higher-quality films. 

Nanoindentation is a highly sensitive technique for assessing the mechanical properties of materials by indenting a sharp tip onto a flat surface, and generating a load-displacement curve. In this project the mechanical response of this material will be explored by selectively etching away material from the top of the GeSn film and indenting the exposed surface. 

It will be also interesting to understand how the GeSn films deform under the nanoindentation tip. Ge is known to undergo various phase transformations to new crystal structures at pressures achieved via nanoindentation loading. It is not known what the effect of Sn will alter the phase transformation pathways. This can be measured using Raman spectroscopy. 

Techniques involved: A number of materials physics and engineering approaches, including nanoindentation, ion-beam scattering, and optical characterisation.

Required background

You have interests in materials science/physics, and would like to communicate and work as part of a wider national and international team.

Project suitability

This research project can be tailored to suit students of the following type(s)

Contact supervisor

Huang, Xingshuo profile

Other supervisor(s)

Bradby, Jodie profile
Williams, Jim profile