Local carrier dynamics around the sub-surface basal-plane stacking faults of GaN studied by spatio-time-resolved cathodoluminescence using a front-excitation-type photoelectron-gun

Local carrier dynamics around the sub-surface basal-plane stacking faults (BSFs) accidentally formed in a low dislocation density c-plane GaN were studied by the spatio-time-resolved cathodoluminescence measurement. A high photoelectron (PE) emission efficiency of the front-excitation-type PE-gun enabled to investigate sub-surface defect structures with low acceleration voltages. As a result, the presence of an energy transfer channel of excitons from neutral donor bound states to I1-type BSF bound states was confirmed. Careful comparisons of cathodoluminescence intensity mapping images taken at 3.305 eV and those corresponding to I1-BSFs indicated the presence of prismatic-plane stacking faults connecting the BSFs into a bundle.