Characterisation of Ga2O3 materials for ultraviolet optoelectronic devices

Wide bandgap semiconductors are the materials of choice for fabricating devices such as solar-blind detectors and ultraviolet (UV) light emitting diodes which are important enabling-technologies for water purification, biological and chemical sensing, flame detection, or communications. With a bandgap of 5 eV, gallium oxide (Ga2O3) is currently thought as one of the most promising materials for next generation UV optoelectronics and power electronics. In particular, the [lowercase alpha] phase of the compound ([lowercase alpha]-Ga2O3) offers unrivalled promises for tuning the operation wavelength of the device in the UV range - hence enabling the fabrication of devices for specific end-applications (e.g. to detect of a given pathogen in water). The [lowercase alpha] phase is however metastable, meaning that reliable synthesis of the material has for long been a challenge - which has been overcome recently. Consequently, little is known, at the experimental or theoretical level, about the mechanisms that lead to light emission/sensing in these materials. It is however vital to understand the inner mechanisms of the material in order to deliver efficient devices to nowadays challenges.
The project will investigate the structural, chemical, and optical properties of [lowercase alpha]-Ga2O3 materials at the nanoscale in order to understand the physical and material mechanisms of photoconduction in [lowercase alpha]-Ga2O3.
The project will build on the world-leading electron microscopy and spectroscopy capabilities of the Semiconductor Spectroscopy and Devices (SSD) group at the University of Strathclyde, which include electron probe micro-analysers (EPMAs) and low-vacuum scanning electron microscopes. The materials will be characterised using the following techniques: cathodoluminescence (CL), electron beam induced current (EBIC), electron channelling contrast imaging (ECCI), electron backscattered diffraction (EBSD), and energy/wavelength dispersive X-ray spectroscopy (EDX/WDX), as well as photoluminescence (PL).