Selective area growth of GaN nanostructures: A key to produce high quality (11–20) a-plane pseudo-substrates

Albert, Steven; Bengoechea-Encabo, Ana; Zúñiga‐Pérez, Jesús; Mierry, P. de; Val, Pablo Arranz; Sánchez-García, M.Á.; Calleja, E.

doi:10.1063/1.4894802

Cited by 12 publications

(4 citation statements)

References 25 publications

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“…Such a high defect density strongly affects the optical and electrical properties, thus limiting the efficiency of nitride-based optoelectronic devices [4][5][6]. Due to higher tolerance to the lattice mismatch, dislocation-free NWs can be grown on different substrates, strongly reducing the production costs, and heterostructures can be incorporated maintaining the high quality crystal structure [7][8][9]. This is particularly advantageous in GaN NWs, where a defect-free structures can be achieved with a possibility to create heterostructures without affecting the material quality, which is particularly useful for devices such as LEDs, photodetectors and resonant tunnelling devices [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Investigation of GaN nanowires containing AlN/GaN multiple quantum discs by EBIC and CL techniques

et al. 2019

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In this work, nanoscale electrical and optical properties of n-GaN nanowires (NWs) containing GaN/AlN multiple quantum discs (MQDs) grown by molecular beam epitaxy (MBE) are investigated by means of single wire I(V) measurements, electron-beam induced current microscopy (EBIC) and cathodoluminescence (CL) analysis. A strong impact of nonintentional AlN and GaN shells on the electrical resistance of individual NWs is put in evidence. The EBIC mappings reveal the presence of two regions with internal electric fields oriented in opposite directions: one in the MQDs region and the other in the adjacent bottom GaN segment. These fields are found to co-exist under zero bias, while under an external bias either one or the other dominates the current collection. In this way EBIC maps allow to locate the current generation within the wire under different bias conditions and to give the first direct evidence of carrier collection from AlN/GaN MQDs. The NWs have been further investigated by photoluminescence (PL) and cathodoluminescence (CL) analyses at low temperature. CL mappings show that the near band edge emission of GaN from the bottom part of the NW is blue-shifted due to the presence of the radial shell. In addition, it is observed that CL intensity drops in the central part of the NWs. Comparing the CL and EBIC maps, this decrease of the luminescence intensity is attributed to an efficient charge splitting effect due to the electric fields in the MQDs region and in the GaN base.

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Section: Introductionmentioning

confidence: 99%

Investigation of GaN nanowires containing AlN/GaN multiple quantum discs by EBIC and CL techniques

et al. 2019

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“…This originates from statistical variations and size-dependent growth properties, which are amplified in the case of self-assembly. − Localized growth in predefined areas of a substrate constitutes one of the solutions to minimize these statistical variations. The growth sites can be defined by a regular array of metal particles catalyzing NW growth or by a patterned growth mask, resulting in selective area epitaxy. − A predefined distance between nanostructures guarantees the most similar growth conditions, given by the growth fluxes and modified by surface diffusion of species on the substrate. , Selective area epitaxy of NWs can result in freestanding or horizontally oriented structures, each configuration being suitable for different applications. ,− Freestanding vertical NWs are ideal for solar cell, light-emitting and photodetecting devices, while horizontal structures have opened new avenues for electronic devices, including quantum computing schemes. − …”

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confidence: 99%

Simultaneous Selective Area Growth of Wurtzite and Zincblende Self-Catalyzed GaAs Nanowires on Silicon

et al. 2021

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Selective area epitaxy constitutes a mainstream method to obtain reproducible nanomaterials. As a counterpart, self-assembly allows their growth without costly substrate preparation, with the drawback of uncontrolled positioning. We propose a mixed approach in which self-assembly is limited to reduced regions on a patterned silicon substrate. While nanowires grow with a wide distribution of diameters, we note a mostly binary occurrence of crystal phases. Self-catalyzed GaAs nanowires form in either a wurtzite or zincblende phase in the same growth run. Quite surprisingly, thicker nanowires are wurtzite and thinner nanowires are zincblende, while the common view predicts the reverse trend. We relate this phenomenon to the influx of Ga adatoms by surface diffusion, which results in different contact angles of Ga droplets. We demonstrate the wurtzite phase of thick GaAs NWs up to 200 nm in diameter in the Au-free approach, which has not been achieved so far to our knowledge.

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“…The broad emissions at around 367 and 371 nm are near-band-edge emissions. 14,24 The increase of longer wavelength component due to the Mg emission shifts the typical emission of GaN from 364 nm to longer wavelength. 25 Besides, emission close to 360 nm was diminished by the long-pass filter.…”

Section: Photoluminescence (Pl) From Gan Surfacementioning

confidence: 99%

Structural Correlation of Random Lasing Performance in Plasma-Induced Surface-Modified Gallium Nitride

Shi

Fujiwara

Kajita

et al. 2022

ACS Appl. Opt. Mater.

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The surface of GaN has been modified by a simple method that irradiates the substrate with Ar plasma and impurity codeposition, which is termed CoDE (Co-Deposition Etching). Unique structures were formed by the assistance of a small amount of Mo deposition without degradation of the crystal structure. The size of protrusions on the structure is influenced by the amount of deposited Mo particles. The mechanism for the structure formation is discussed based on transmission electron microscopy (TEM) observations and energy dispersive X-ray spectroscopy (EDS) measurements. Based on the GaN surface roughness, we have demonstrated random laser action in the UV region under photoexcitation. The lowest threshold (0.06 J/cm 2 ) for random lasing was observed where the size of the structure is larger than 0.05 μm 2 , which was formed under conditions with the least amount of deposition. The correlation between the submicro/nanosize structures generated by plasma irradiation and lasing was evaluated in detail. The critical parameter to optimize the random lasing was determined to be the size of structures that can be modified by the Mo deposition rate. The results confirmed that the emission properties can be controlled by the processing conditions. This random laser fabrication technique is expected to be widely applicable to various direct-bandgap compound semiconductors.

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Selective area growth of GaN nanostructures: A key to produce high quality (11–20) a-plane pseudo-substrates

Cited by 12 publications

References 25 publications

Investigation of GaN nanowires containing AlN/GaN multiple quantum discs by EBIC and CL techniques

Investigation of GaN nanowires containing AlN/GaN multiple quantum discs by EBIC and CL techniques

Simultaneous Selective Area Growth of Wurtzite and Zincblende Self-Catalyzed GaAs Nanowires on Silicon

Structural Correlation of Random Lasing Performance in Plasma-Induced Surface-Modified Gallium Nitride

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