Photoluminescence of exciton and biexciton in GaN nanocolumns

Kouyama, Kazuaki; Inoue, Masaya; Inose, Yuta; Suzuki, Naoki; Sekiguchi, Hiroto; Kunugita, Hideyuki; Ema, Kazuhiro; Kikuchi, Akihiko; Kishino, Katsumi

doi:10.1016/j.jlumin.2007.12.021

Cited by 9 publications

(7 citation statements)

References 5 publications

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“…Due to lateral strain relaxation and other possible mechanisms, the TD density in a GaN NC can be extremely low. [11][12][13][14][15][16][17][18][19][20][21] It is expected that the coalescence overgrowth of such NCs can lead to a high-quality GaN overgrown layer. However, it was found that to achieve high-quality coalescence overgrowth, a regular arrangement of vertical and parallel NCs is preferred.…”

Section: Introductionmentioning

confidence: 99%

Threading dislocation evolution in patterned GaN nanocolumn growth and coalescence overgrowth

Chen

Shiao

Tang

et al. 2009

Journal of Applied Physics

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Effects of growth interruption on the optical and the structural properties of InGaN/GaN quantum wells grown by metalorganic chemical vapor deposition Effect of buffer layers and stacking faults on the reduction of threading dislocation density in GaN overlayers grown by metalorganic chemical vapor deposition Threading dislocation ͑TD͒ evolution during patterned GaN nanocolumn ͑NC͒ growth and coalescence overgrowth with metal-organic chemical vapor deposition is studied based on the comparisons of NC and coalescence overgrowth samples of different NC cross-section diameters and spacing sizes. From the measurement results of depth-dependent x-ray diffraction and cross-section transmission electron microscopy, it is found that the TD density in an NC depends on the patterned hole size for NC growth. Also, the TD formation at the beginning of coalescence overgrowth is related to the NC spacing size. Although the TD density at the bottom of the overgrown layer is weakly dependent on NC and spacing sizes, at its top surface, the TD density strongly relies on NC size. Among the overgrowth samples of different NC diameters and spacing sizes with a fixed NC diameter/spacing ratio, the one with the smallest size and spacing leads to the lowest TD density, the largest lateral domain size, and the highest photoluminescence efficiency. Also, the optical and crystal qualities at the surfaces of all the overgrowth samples are superior to those of a GaN template.

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Section: Introductionmentioning

confidence: 99%

Threading dislocation evolution in patterned GaN nanocolumn growth and coalescence overgrowth

Chen

Shiao

Tang

et al. 2009

Journal of Applied Physics

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“…In this paper we have confirmed our supposition by distance-dependent PL measurements. Moreover, we have made a detailed analysis of the large biexciton binding energy which was also observed in the previous work [5].…”

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confidence: 72%

“…3 Exciton and biexciton binding energies We also observed biexciton emissions from the large-diameter samples [5]. Although the column diameter (~150 nm) is much larger than the exciton Bohr radius (3 nm), the observed biexciton binding energies were ~11 meV, which is almost twice as large as that in bulk sample (~5.7 meV) [6].…”

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confidence: 76%

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Exciton and biexciton properties in GaN nanocolumn: dependence on morphology and diameter

Kouyama

Inoue

Inose

et al. 2008

Phys. Status Solidi (c)

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We have investigated how the morphology and diameter of GaN nanocolumn affect the optical properties of exciton and biexciton. We measured photoluminescence (PL) of excitons in GaN nanocolumns at low temperature and found that the PL spectra depend on the column diameter. Changing the distance between the sample and the collimating lens, it was established that this phenomenon is due to the z ‐polarized PL radiated from the side surface. This result proves that the nano‐scale morphology produces a change in the optical properties. In addition, to elucidate the mechanism causing the increase of the biexciton binding energy observed in a previous experiment, we calculated the exciton binding energies by the variational method and also estimated their sizes. From the calculated results we can expect that the only biexcitons experience spatial confinement effect even when the nanocolumn width is much larger than the exciton Bohr radius. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…4 also show that the PL peak shifts in different SiC nanorod arrays. The shift of the PL peak is attributed to the light emission from the top and the side surfaces of the nanorods with different diameters [28]. The shift can also be caused by the light extraction efficiency that affected by the disorder and defect present in the nanorod arrays.…”

Section: Resultsmentioning

confidence: 99%

Facile synthesis and improved photoluminescence of periodic SiC nanorod arrays by SiO2 templates-assisted magnetron sputtering method

Yang

et al. 2012

Journal of Alloys and Compounds

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Photoluminescence of exciton and biexciton in GaN nanocolumns

Cited by 9 publications

References 5 publications

Threading dislocation evolution in patterned GaN nanocolumn growth and coalescence overgrowth

Threading dislocation evolution in patterned GaN nanocolumn growth and coalescence overgrowth

Exciton and biexciton properties in GaN nanocolumn: dependence on morphology and diameter

Facile synthesis and improved photoluminescence of periodic SiC nanorod arrays by SiO2 templates-assisted magnetron sputtering method

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