Document Type
Article
Original Publication Date
2012
Journal/Book/Conference Title
Journal of Applied Physics
Volume
111
Issue
2
DOI of Original Publication
10.1063/1.3673851
Date of Submission
October 2015
Abstract
Carrier dynamics in hydride vapor phase epitaxy grown bulk GaN with very low density of dislocations, 5–8 × 105 cm−2, have been investigated by time-resolved photoluminescence (PL), free carrier absorption, and light-induced transient grating techniques in the carrier density range of 1015 to ∼1019 cm−3 under single and two photon excitation. For two-photon carrier injection to the bulk (527 nm excitation), diffusivity dependence on the excess carrier density revealed a transfer from minority to ambipolar carrier transport with the ambipolar diffusion coefficient D a saturating at 1.6 cm2/s at room temperature. An extremely long lifetime value of 40 ns, corresponding to an ambipolar diffusion length of 2.5 μm, was measured at 300 K. A nearly linear increase of carrier lifetime with temperature in the 80–800 K range and gradual decrease of D pointed out a prevailing mechanism of diffusion-governed nonradiative recombination due to carrier diffusive flow to plausibly the grain boundaries. Under single photon excitation (266 and 351 nm), subnanosecond transients of PL decay and their numerical modeling revealed fast processes of vertical carrier diffusion, surface recombination, and reabsorption of emission, which mask access to pure radiative decay.
Rights
Scajev, P., Jarasiunas, K., & Okur, S., et al. Carrier dynamics in bulk GaN. Journal of Applied Physics, 111, 023702 (2012). Copyright © 2012 American Institute of Physics.
Is Part Of
VCU Electrical and Computer Engineering Publications
Comments
Originally published at http://dx.doi.org/10.1063/1.3673851