Free carrier dynamics of InN nanorods investigated by time-resolved terahertz spectroscopy

Ultrafast time-resolved terahertz spectroscopy is employed to investigate the carrier dynamics of indium nitride (InN) nanorod arrays and an epitaxial film. Transient differential transmission of terahertz wave shows that hot carrier cooling and defect-related nonradiative recombination are the common carrier relaxation processes for InN film and nanorods. However, the electrons confined in the narrow structure of nanorods are significantly affected by the carrier diffusion process near the surface, which causes the abnormally long relaxation time for nanorods.