Native point defect formation in flash sintered ZnO studied by depth-resolved cathodoluminescence spectroscopy

Abstract

Depth-resolved cathodoluminescence spectroscopy studies of flash sintered ZnO reveal that thermal runaway induces the formation of native point defects inside individual grains. Defects associated with oxygen vacancies (VO) form preferentially, contributing additional donors that increase conductivity within the grains of the polycrystalline material. Hyperspectral imaging of the granular cross sections shows filaments of increased VO following thermal runaway between the capacitor anode and cathode, supporting a heating mechanism localized on a granular scale. Within the grains, these defects form preferentially inside rather than at their boundaries, further localizing the dominant heating mechanism.