As4 overpressure effects on the phase purity of cubic GaN layers grown on GaAs substrates by RF-MBE

Casallas-Moreno, Y.L.; Gallardo-Hernández, S.; Ruiz-Zepeda, Francisco; Monroy, B.M.; Hernández–Hernández, A.; Herrera-Gómez, Alberto; Escobosa, A.; Santana, G.; Ponce, Arturo; López‐López, M.

doi:10.1016/j.apsusc.2015.06.054

Cited by 15 publications

(7 citation statements)

References 30 publications

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“…High-quality wurtzite GaN has been demonstrated on Si, SiC, and sapphire substrates using MBE and MOCVD, but it has remained difficult to achieve GaN epitaxial growth directly on conventional III–V materials due to the difference in crystal structure. − In this work, we have demonstrated crystalline GaN nanostructures epitaxially grown on GaInP 2 without the formation of extensive defects and dislocations using plasma-assisted MBE. High-resolution electron microscopy imaging of the GaN/3J structure confirms a highly crystalline GaN nanostructure epitaxially grown on a GaInP 2 surface with furcated topography.…”

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confidence: 68%

Stable Unassisted Solar Water Splitting on Semiconductor Photocathodes Protected by Multifunctional GaN Nanostructures

et al. 2019

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Producing hydrogen by unassisted solar water splitting is one essential step to make direct solar fuel conversion a viable energy source. To date, however, there has been no demonstration of stable photoelectrodes for high-efficiency photoelectrochemical water splitting. In this work, we report that a GaInP 2 /GaAs/Ge triple-junction (3J) photocathode protected by multifunctional GaN nanostructures can enable both efficient and relatively stable solar water splitting. A 12.6% solar-to-hydrogen (STH) efficiency is measured without any external bias. Of particular importance, we demonstrate relatively stable solar water splitting for 80 h in three-electrode configuration and 57 h in twoelectrode measurement at zero bias. This is the best reported stability for multijunction III-V semiconductor photocathodes in two-electrode configuration to our knowledge. The multifunctional GaN nanostructure significantly reduces the charge transfer resistance at the semiconductor/electrolyte interface and protects III−V materials against corrosion. Such multifunctional GaN photocatalytic nanostructures provide a new pathway to improve the performance of conventional photoelectrodes to achieve both efficient and stable unassisted solar water splitting.

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confidence: 68%

Stable Unassisted Solar Water Splitting on Semiconductor Photocathodes Protected by Multifunctional GaN Nanostructures

et al. 2019

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“…Due to these advantages, nitrides in the cubic phase are strong candidates to develop semiconductor devices such as LEDs and photovoltaic devices. However, c-GaN is metastable, causing its growth a difficult challenge 12 . An additional drawback is that under typical growth conditions hexagonal GaN has an intrinsic n-type nature, and if GaN is aimed for optoelectronic applications, then the development of p-type doping of GaN is fundamental for any p–n junction-based device.…”

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confidence: 99%

Study of the heavily p-type doping of cubic GaN with Mg

Hernández-Gutiérrez

Casallas-Moreno

Rangel-Kuoppa

et al. 2020

Sci Rep

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We have studied the Mg doping of cubic GaN grown by plasma-assisted Molecular Beam Epitaxy (PA-MBE) over GaAs (001) substrates. In particular, we concentrated on conditions to obtain heavy p-type doping to achieve low resistance films which can be used in bipolar devices. We simulated the Mg-doped GaN transport properties by density functional theory (DFT) to compare with the experimental data. Mg-doped GaN cubic epitaxial layers grown under optimized conditions show a free hole carrier concentration with a maximum value of 6 × 1019 cm−3 and mobility of 3 cm2/Vs. Deep level transient spectroscopy shows the presence of a trap with an activation energy of 114 meV presumably associated with nitrogen vacancies, which could be the cause for the observed self-compensation behavior in heavily Mg-doped GaN involving Mg-VN complexes. Furthermore, valence band analysis by X-ray photoelectron spectroscopy and photoluminescence spectroscopy revealed an Mg ionization energy of about 100 meV, which agrees quite well with the value of 99.6 meV obtained by DFT. Our results show that the cubic phase is a suitable alternative to generate a high free hole carrier concentration for GaN.

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“…The GaN layer was grown at 720 °C employing a Ga-beam equivalent pressure of 2 × 10 −7 Torr and a N 2 flux of 0.25 sccm with an RFpower of 150 W, which result in Ga-rich but near stochiometric conditions, that are known to be optimal for the GaN/ GaAs heteroepitaxy on nominal flat (100) substrates. 18,19) GaN with cubic phase was obtained, as observed from the selected area electron diffraction (SAD) pattern shown in the upper left corner of Fig. 1(a).…”

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confidence: 94%

“…17) Details concerning GaN growth over GaAs substrates with (100) nominal orientation (flat substrates) have been reported elsewhere. 18) For the present work we employed GaAs(100) substrates misoriented 10°towards the [011] direction [GaAs (100)-10°]. This substrate misorientation produces atomic surface steps with a terrace width of 1 nm.…”

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confidence: 99%

Control of the formation of self-assembled nano-voids at the GaN/GaAs interface

Perez-Hernandez

Zambrano-Serrano

Gallardo-Hernández

et al. 2021

Appl. Phys. Express

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The self-assembling of nanovoids with a precisely controlled depth at the GaN/GaAs interface is reported and their formation mechanism discussed. During the very early stages of GaN growth by molecular beam epitaxy over GaAs(100) misoriented substrates, nano-pits are formed by chemical reactions of gallium and nitrogen with a GaAs sacrificial layer. The GaAs sacrificial layer is grown on top of a GaAs/AlGaAs superlattice that is used to efficiently stop the in-depth etch and to promote lateral etching. Thus, a nanostructure of wide voids and pedestals is self-assembled and confined at the interface. As an application, the lift-off of GaN epilayers from the substrate was carried out successfully, a fact that opens up the applicability of this process in other semiconductor systems.

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As4 overpressure effects on the phase purity of cubic GaN layers grown on GaAs substrates by RF-MBE

Cited by 15 publications

References 30 publications

Stable Unassisted Solar Water Splitting on Semiconductor Photocathodes Protected by Multifunctional GaN Nanostructures

Stable Unassisted Solar Water Splitting on Semiconductor Photocathodes Protected by Multifunctional GaN Nanostructures

Study of the heavily p-type doping of cubic GaN with Mg

Control of the formation of self-assembled nano-voids at the GaN/GaAs interface

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