Impact of Proton and Neutron Irradiation on Carrier Transport Properties in GA2O3

This project studies the properties of minority charge carriers in beta gallium oxide (β -Ga2O3). The behavior of minority carriers is of high importance as it greatly affects conduction and consequently device performance. Cathodoluminescence (CL) spectroscopy and EBIC (Electron Beam Induced Current) are the main experimental techniques used to study minority carrier behavior. High energy radiation affects minority carrier properties through damage to the material and through the production of carrier traps that reduce the conductivity and mobility of the material. In this investigation, we study the effects of various kinds of high energy radiation on properties of minority carriers in silicon-doped β -Ga2O3. The thermal activation energy of the reference (non-irradiated) sample was 40.9 meV, which is ascribed to silicon-donors. CL measurements indicate a slightly indirect bandgap energy of 4.9 eV. Under 10 MeV proton irradiation, the thermal activation energies increase. This increase is attributable to high order defects and their influence on carrier lifetimes. Differentiating itself from other forms of radiation, neutron irradiation creates disordered regions in β - Ga2O3 as opposed to just point defects, resulting in the lowest carrier removal rate because of the lowest average non-ionizing energy loss. Measurements show that β -Ga2O3 is more resistant to radiation damage than some other wide bandgap semiconductors due to its higher displacement threshold energy, which is inversely proportional to the lattice constant