Defect reduction in GaN/(0001)sapphire films grown by molecular beam epitaxy using nanocolumn intermediate layers

Cherns, D.; Meshi, Louisa; Griffiths, Ian; Khongphetsak, S; Novikov, S.V.; Farley, N. R. S.; Campion, R. P.; Foxon, C.T.

doi:10.1063/1.2899944

Cited by 65 publications

(53 citation statements)

References 16 publications

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“…39 The tall and thin nanorods are proven to have Ga-polarity, and the shorter wider nanorods are N-polar, as measured by CBED. 61 The morphology of the GaN nanorods with different polarities is shown in Fig. 12.…”

Section: B Catalyst-free Gan Nanorod Growthmentioning

confidence: 99%

GaN based nanorods for solid state lighting

Li¹,

Waag

2012

Journal of Applied Physics

488

394

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In recent years, GaN nanorods are emerging as a very promising novel route toward devices for nano-optoelectronics and nano-photonics. In particular, core-shell light emitting devices are thought to be a breakthrough development in solid state lighting, nanorod based LEDs have many potential advantages as compared to their 2 D thin film counterparts. In this paper, we review the recent developments of GaN nanorod growth, characterization, and related device applications based on GaN nanorods. The initial work on GaN nanorod growth focused on catalyst-assisted and catalyst-free statistical growth. The growth condition and growth mechanisms were extensively investigated and discussed. Doping of GaN nanorods, especially p-doping, was found to significantly influence the morphology of GaN nanorods. The large surface of 3 D GaN nanorods induces new optical and electrical properties, which normally can be neglected in layered structures. Recently, more controlled selective area growth of GaN nanorods was realized using patterned substrates both by metalorganic chemical vapor deposition (MOCVD) and by molecular beam epitaxy (MBE). Advanced structures, for example, photonic crystals and DBRs are meanwhile integrated in GaN nanorod structures. Based on the work of growth and characterization of GaN nanorods, GaN nanoLEDs were reported by several groups with different growth and processing methods. Core/shell nanoLED structures were also demonstrated, which could be potentially useful for future high efficient LED structures. In this paper, we will discuss recent developments in GaN nanorod technology, focusing on the potential advantages, but also discussing problems and open questions, which may impose obstacles during the future development of a GaN nanorod based LED technology.

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Section: B Catalyst-free Gan Nanorod Growthmentioning

confidence: 99%

GaN based nanorods for solid state lighting

Li¹,

Waag

2012

Journal of Applied Physics

488

394

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“…As a matter of fact, recent studies by convergent beam electron diffraction have established that GaN NCs, grown by us or other groups by MBE, do grow with Ga polarity. 27,28 In addition, high-resolution transmission electron microscopy measurements have established that our NCs contain no extended defects ͑Fig. 3͒, thus no inversion domains.…”

Section: Time-integrated Photoluminescencementioning

confidence: 99%

Time-resolved spectroscopy on GaN nanocolumns grown by plasma assisted molecular beam epitaxy on Si substrates

Corfdir

Lefèbvre

Ristić

et al. 2009

Journal of Applied Physics

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A detailed study of excitons in unstrained GaN nanocolumns grown by plasma assisted molecular beam epitaxy on silicon substrates is presented. The time-integrated and time-resolved photoluminescence spectra do not depend significantly on the ͑111͒ or ͑001͒ Si surface used. However, an unusually high relative intensity of the two-electron satellite peak of the dominant donor-bound exciton line is systematically observed. We correlate this observation with the nanocolumn morphology determined by scanning electron microscopy, and therefore propose an interpretation based on the alteration of wave functions of excitonic complexes and of donor states by the proximity of the semiconductor surface. This explanation is supported by a model that qualitatively accounts for both relative intensities and time decays of the photoluminescence lines.

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“…To improve the efficiency of GaN-based devices, various strategies are employed with the aim to reduce the high dislocation densities inherent to the heteroepitaxial growth of GaN and avoiding polarization fields which are detrimental to optical devices [2,3]. However, these growth strategies often result in the formation of stacking faults: Especially the growth of non-and semi-polar GaN layers [4][5][6][7][8] as well as epitaxial-lateral overgrowth [9][10][11][12][13][14] or the coalescence overgrowth of nanowires [15][16][17][18] are associated with the formation of basal-plane stacking faults independent of which growth technique is used. As a consequence, the emission characteristics and transport properties of the layers are changed [11,19].…”

Section: Introductionmentioning

confidence: 99%

Luminescence associated with stacking faults in GaN

Lähnemann¹,

Jahn²,

Brandt³

et al. 2014

J. Phys. D: Appl. Phys.

101

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Abstract. Basal-plane stacking faults are an important class of optically active structural defects in wurtzite semiconductors. The local deviation from the 2H stacking of the wurtzite matrix to a 3C zinc-blende stacking induces a bound state in the gap of the host crystal, resulting in the localization of excitons. Due to the two-dimensional nature of these planar defects, stacking faults act as quantum wells, giving rise to radiative transitions of excitons with characteristic energies. Luminescence spectroscopy is thus capable of detecting even a single stacking fault in an otherwise perfect wurtzite crystal. This review draws a comprehensive picture of the luminescence properties related to stacking faults in GaN. The emission energies associated with different types of stacking faults as well as factors that can shift these energies are discussed. In this context, the importance of the quantum-confined Stark effect in these zinc-blende/wurtzite heterostructures, which results from the spontaneous polarization of wurtzite GaN, is underlined. This discussion is extended to zinc-blende segments in a wurtzite matrix. Furthermore, other factors affecting the emission energy and linewidth of stacking fault-related peaks as well as results obtained at room temperature are addressed. The considerations presented in this article should be transferable also to other wurtzite semiconductors.

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Defect reduction in GaN/(0001)sapphire films grown by molecular beam epitaxy using nanocolumn intermediate layers

Cited by 65 publications

References 16 publications

GaN based nanorods for solid state lighting

GaN based nanorods for solid state lighting

Time-resolved spectroscopy on GaN nanocolumns grown by plasma assisted molecular beam epitaxy on Si substrates

Luminescence associated with stacking faults in GaN

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