| Autor: |
Dimkou I; Univ. Grenoble-Alpes, CEA, LETI, F-38000 Grenoble, France., Harikumar A, Donatini F, Lähnemann J, den Hertog MI, Bougerol C, Bellet-Amalric E, Mollard N, Ajay A, Ledoux G, Purcell ST, Monroy E |
| Jazyk: |
angličtina |
| Zdroj: |
Nanotechnology [Nanotechnology] 2020 May 15; Vol. 31 (20), pp. 204001. Date of Electronic Publication: 2020 Jan 27. |
| DOI: |
10.1088/1361-6528/ab704d |
| Abstrakt: |
In this paper, we describe the design and characterization of 400 nm long (88 periods) Al x Ga 1-x N/AlN (0 ≤ x ≤ 0.1) quantum dot superlattices deposited on self-assembled GaN nanowires for application in electron-pumped ultraviolet sources. The optical performance of GaN/AlN superlattices on nanowires is compared with the emission of planar GaN/AlN superlattices with the same periodicity and thickness grown on bulk GaN substrates along the N-polar and metal-polar crystallographic axes. The nanowire samples are less sensitive to nonradiative recombination than planar layers, attaining internal quantum efficiencies (IQE) in excess of 60% at room temperature even under low injection conditions. The IQE remains stable for higher excitation power densities, up to 50 kW cm -2 . We demonstrate that the nanowire superlattice is long enough to collect the electron-hole pairs generated by an electron beam with an acceleration voltage V A = 5 kV. At such V A , the light emitted from the nanowire ensemble does not show any sign of quenching under constant electron beam excitation (tested for an excitation power density around 8 kW cm -2 over the scale of minutes). Varying the dot/barrier thickness ratio and the Al content in the dots, the nanowire peak emission can be tuned in the range from 340 to 258 nm. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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