Small size GaN nanorods (GaN NRs) show new features of the photoluminescence (PL) associated with the enhanced surface effects and the strong electron-phonon coupling. A dominant emission is observed at 3.43 eV; a lower energy with respect to the commonly reported (DXA)-X-0 peak for thicker NRs. The phonon replicas of the silent B1l acoustic phonon mode are well represented in the PL spectra at temperatures up to 150 K inferring the enhanced Frohlich electron-phonon coupling. The B1l phonon mode was previously detected for the grown GaN NRs by resonant Raman scattering under resonance excitation. The enhanced electron-phonon coupling through Frohlich interaction is proven by the calculated Huang-Rhys factor. The low-energy dominant peak intensity is around six times the (DXA)-X-0 peak intensity indicating that the majority of excitons occupy the surface shell of GaN NRs. This study provides new insights on small-size GaN NRs that greatly influence their physical properties for applications in optoelectronics, UV and blue lasers, and high-temperature/high-power electronic devices. (C) 2021 Elsevier B.V. All rights reserved.
NSTL
Elsevier