Optical properties of GaN nanorods grown catalyst‐free on r‐plane sapphire

Sebald, K.; Kalden, J.; Voss, T.; Gutowski, J.; Aschenbrenner, T.; Kunert, Gerd; Kruse, C.; Figge, S.; Hommel, D.

doi:10.1002/pssc.200880945

Cited by 5 publications

(4 citation statements)

References 17 publications

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“…For clarity, the inset in figure 4 shows the NBE spectrum together with a multiple Gaussian line fit. The energy positions of the emission lines are found at 3.478, 3.476, 3.473 and 3.465 eV, respectively, which are in good agreement with previous reports [5,34,40]. Using an exciton binding energy of E bX =25 meV [41,42], this relates to a binding energy of excitons to donors of E DX =5 meV and to acceptors of E AX =13 meV.…”

Section: Ti Pl Of Bare Gan Nanorodssupporting

confidence: 90%

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Emission dynamics of hybrid plasmonic gold/organic GaN nanorods

et al. 2017

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We studied the emission of bare and aluminum quinoline (Alq)/gold coated wurtzite GaN nanorods by temperature- and intensity-dependent time-integrated and time-resolved photoluminescence (PL). The GaN nanorods of ∼1.5 μm length and ∼250 nm diameter were grown by plasma-assisted molecular beam epitaxy. Gold/Alq coated GaN nanorods were synthesized by organic molecular beam deposition. The near band-edge and donor-acceptor pair luminescence was investigated in bare GaN nanorods and compared with multilevel model calculations providing the dynamical parameters for electron-hole pairs, excitons, impurity bound excitons, donors and acceptors. Subsequently, the influence of a 10 nm gold coating without and with an Alq spacer layer was studied and the experimental results were analyzed with the multilevel model. Without a spacer layer, a significant PL quenching and lifetime reduction of the near band-edge emission is found. The behavior is attributed to surface band-bending and Förster energy transfer from excitons to surface plasmons in the gold layer. Inserting a 5 nm Alq spacer layer reduces the PL quenching and lifetime reduction which is consistent with a reduced band-bending and Förster energy transfer. Increasing the spacer layer to 30 nm results in lifetimes which are similar to uncoated structures, showing a significantly decreased influence of the gold coating on the excitonic dynamics.

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Section: Ti Pl Of Bare Gan Nanorodssupporting

confidence: 90%

“…These donors are thought to be mostly nitrogen vacancies (V N ), with some contribution of oxygen impurities. The growth process has been described earlier in more detail [5,34].…”

Section: Fabrication and Structural Characterization Of Gan Nanorods ...mentioning

confidence: 99%

Emission dynamics of hybrid plasmonic gold/organic GaN nanorods

et al. 2017

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“…The NRs are N-polar [12] and possess a high crystalline quality. The D 0 X A recombination has a spectral linewidth of 1.2 meV in microphotoluminescence (µPL) spectra at 4 K measured for NR ensembles as well as for single NRs [14]. This value is one of the lowest reported so far for GaN NRs.…”

Section: Growth and Crystal Habitmentioning

confidence: 78%

Light-emitting diode based on mask- and catalyst-free grown N-polar GaN nanorods

et al. 2011

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We report on the fabrication of a light-emitting diode based on GaN nanorods containing InGaN quantum wells. The unique system consists of tilted N-polar nanorods of high crystalline quality. Photoluminescence, electroluminescence, and spatially resolved cathodoluminescence investigations consistently show quantum well emission around 2.6 eV. Scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy measurements reveal a truncated shape of the quantum wells with In contents of (15 ± 5)%.

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“…The indices A and B point to the origin of the hole from the A or the B valence band, respectively. A more detailed investigation of the m-PL characteristics of these nanorods is presented elsewhere [15,31]. Figure 10 shows the temperature dependence of the nearband-edge photoluminescence of a nanorod ensemble from 4 K to room temperature (300 K) using a logarithmic intensity scale.…”

Section: Structural and Optical Propertiesmentioning

confidence: 99%

Catalyst free self‐organized grown high‐quality GaN nanorods

Aschenbrenner

Kunert

Freund

et al. 2011

Physica Status Solidi (b)

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Highly ordered GaN nanorods were grown self-organized and without catalyst on r-plane sapphire by molecular beam epitaxy while the AlN nucleation sites for the nanorods were provided by a nitridation process using a metal-organic vapor-phase epitaxy system. The growth window for the nanorod formation was analysed in detail and turned out to be very sensitive with respect to the growth temperature. The nanorods are symmetrically tilted with an inclination angle of 628 between the substrate and the nanorods. The mirror axis is the c-direction of the compact GaN layer surrounding the roots of the nanocolumns. Methods for the control of the nanorod density and the suppression of one nanorod growth direction are presented. The results indicate a diffusion based growth mechanism. Transmission electron microscopy studies and high resolution X-ray diffraction (HRXRD) polar plots reveal the epitaxial relationship between substrate, compact GaN layer and nanorods. The nanorods grow in c-direction and the side facets are m-planes. Transmission electron microscopic and optical analysis of the nanorods reveal the good structural and optical properties, respectively. A full width at half maximum (FWHM) of 1.2 meV of the donor-bound exciton emission was measured for both the ensemble and single free-standing nanorods. Successful n-and Mg-doping of nanorods was verified by a strong increase of the micro-photoluminescence intensity of the respective donor-bound and acceptor-bound exciton emission peak in comparison to an undoped sample.The background shows a secondary electron microscope image (angle of 108 between sample surface and electron beam) of the nanorods. Superimposed to the SEM image, a typical microphotoluminescence spectrum of the excitonic emission of an ensemble at 25 K is presented. The donor-bound, acceptorbound and free exciton lines are labelled with D 0 X, A 0 X and FX, respectively.

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Optical properties of GaN nanorods grown catalyst‐free on r‐plane sapphire

Cited by 5 publications

References 17 publications

Emission dynamics of hybrid plasmonic gold/organic GaN nanorods

Emission dynamics of hybrid plasmonic gold/organic GaN nanorods

Light-emitting diode based on mask- and catalyst-free grown N-polar GaN nanorods

Catalyst free self‐organized grown high‐quality GaN nanorods

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