Figure 4
From: On the phenomenon of large photoluminescence red shift in GaN nanoparticles
Schematic representations of potential fluctuation and surface states caused by defects and band distortion. (a) Bulk GaN. (b) NP thoroughly depleted at low excitation power/low temperature. (c) NP with high carrier concentration at high excitation power/high temperature has a surface depletion region with small width. Arrows indicate recombination of free electrons and bound holes.