Abstract
We investigate the photoluminescence (PL) spectra of ZnO nanorod (NR) and C(carbon)-aided NR arrays from 10 to 300 K. The activation energy of the donor-bound exciton of the ZnO NRs was determined to be 11.3 meV ranging over 10–300 K. The decreasing behavior of the PL intensity for the C(carbon)-aided ZnO NRs exhibited two activation energies, i.e., 3.2 and 65.8 meV at T < 70 K and T > 70 K, respectively. The activation energy for the donor-bound exciton decreased because of stronger quantum confinement in the C(carbon)-aided ZnO NRs than that of the ZnO NRs. We attribute these results to lower lattice mismatch, a larger surface-to-volume ratio, and the dense structure of the vertically orientated hexagonal pillars with flat faceted surfaces in the C(carbon)-aided ZnO NRs. A considerable exciton binding energy of 65.8 meV from the C(carbon)-aided ZnO NR arrays produced luminescence stably at 300 K. In addition, PL spectra demonstrated that the luminescence intensities of the C(carbon)-aided ZnO NRs were higher than that of the ZnO NRs because of weak exciton-phonon coupling. The higher PL intensities of the C(carbon)-aided ZnO NRs suggest that these structures might feature improved performance in optoelectronic nano-devices manufactured from ZnO NRs.
Original language | English |
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Article number | 144271 |
Journal | Applied Surface Science |
Volume | 501 |
DOIs | |
State | Published - 31 Jan 2020 |
Keywords
- Exciton
- Photoluminescence
- Single crystal
- ZnO nanorods