Surface oxide relationships to band bending in GaN

Garcia, Michael A.; Wolter, Scott D.; Kim, Tong-Ho; Choi, Sunghee; Baier, Jamie; Brown, April S.; Losurdo, Maria; Bruno, Giovanni

doi:10.1063/1.2158701

Cited by 48 publications

(26 citation statements)

References 27 publications

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“…While the exciton distribution is expected to broaden towards the inside of the sample before recombination, the influence of nonradiative surface states on the timeresolved PL behaviour cannot be ignored. The Ga face GaN surface discussed here has intrinsic empty surface states in the bandgap about 0.6 eV below the conduction band edge according to recent theoretical estimates [11], experimentally slightly deeper states are found for a clean surface [12,13]. These surface states are certainly expected to be electrically active, they will pin the Fermi level at the surface and participate in recombination of ex-citons (and carriers).…”

Section: Samples and Experimental Proceduresmentioning

confidence: 62%

“…These surface states are certainly expected to be electrically active, they will pin the Fermi level at the surface and participate in recombination of ex-citons (and carriers). The oxidized surface is found to enhance the nonradiative surface recombination rate [13]. Samples handled in the air have a thin (about 1-3 nm) disordered oxide layer at the surface, with a high density of defects.…”

Section: Samples and Experimental Proceduresmentioning

confidence: 99%

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Recombination of free and bound excitons in GaN

Ḿonemar

Paskov

Bergman

et al. 2008

Physica Status Solidi (b)

109

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Section: Samples and Experimental Proceduresmentioning

confidence: 62%

Section: Samples and Experimental Proceduresmentioning

confidence: 99%

Recombination of free and bound excitons in GaN

Ḿonemar

Paskov

Bergman

et al. 2008

Physica Status Solidi (b)

109

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“…Position of VBM and core level BE can also be affected due to varying order of surface oxidation of GaN surface. 80 However, in our case, surface oxidation will not affect the data analysis as we have similar order of surface contamination on all our analyzed sample ( Table 2). We have not observed any defect induced states in the energy gap (between VBM and E F ).…”

mentioning

confidence: 99%

Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

et al. 2015

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aWe have grown homoepitaxial GaN nanowall networks on GaN template using an ultra-high vacuum laser assisted molecular beam epitaxy system by ablating solid GaN target under a constant r.f. nitrogen plasma ambient. The effect of laser repetition rate in the range of 10 to 30 Hz on the structural properties of the GaN nanostructures has been studied using high resolution X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy. The variation of the laser repetition rate affected the tip width and pore size of the nanowall networks. The z-profile Raman spectroscopy measurements revealed the GaN nanowall network retained the same strain present in the GaN template. The optical properties of these GaN nanowall networks have been studied using photoluminescence and ultrafast spectroscopy and an enhancement of optical band gap has been observed for the nanowalls having a tip width of 10-15 nm due to the quantum carrier confinement effect at the wall edges. The electronic structure of the GaN nanowall networks has been studied using X-ray photoemission spectroscopy and it has been compared to the GaN template. The calculated Ga/N ratio is largest ($2) for the GaN nanowall network grown at 30 Hz. Surface band bending decreases for the nanowall network with the lowest tip width. The homoepitaxial growth of porous GaN nanowall networks holds promise for the design of nitride based sensor devices.

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“…23 Secondary ion mass spectrometry profiles show that the oxygen concentration increases dramatically towards the surface due to the formation of a native oxide, predominantly of the form Ga 2 O 3 , which grows after the exposure of the sample to the atmosphere. [24][25][26][27] The use of a semiconductor detector, in combination with a multichannel analyzer, allows the energy filtering of the N K fluorescence photons and the elimination of the oxygen contribution in N K edge spectra. The detector was positioned normal to the beam in the horizontal plane.…”

Section: Growth Conditions and Experimental Detailsmentioning

confidence: 99%

Modification of the N bonding environment in GaN after high-dose Si implantation: An x-ray absorption study

Katsikini

Pinakidou

Paloura

et al. 2007

Journal of Applied Physics

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The microstructure and electronic structure of epitaxially grown GaN, that has been subjected to high-dose Si implantation, is studied using x-ray absorption fine structure (XAFS) spectroscopy. More specifically, XAFS is used to probe the formation of N–Si bonds and to study the implantation induced distortions in the lattice. The analysis of the extended XAFS spectra reveals that implantation with 100keV Si ions with a fluence equal to 1×1018cm−2 renders the material amorphous and promotes the formation of Si–N bonds with a bond length equal to that corresponding in Si3N4. In addition to that, the N–Ga distances increase by ∼5% due to the lattice expansion caused by the incorporation of the Si ions and the formation of point and extended defects. The absence of long or midrange order is also verified by the near edge XAFS (NEXAFS) spectra where the characteristic peaks are smeared out. However, a characteristic sharp resonance line, that appears about 1eV above the absorption edge, indicates the existence of defect states which are strongly localized on the N atoms, most probably defect complexes involving N dangling bonds. In order to provide additional evidence on the nature of the implantation induced changes we resorted to simulations of the NEXAFS spectra using the FEFF8 code by applying chemical and lattice deformations in the immediate environment of the absorbing atom as well as to larger clusters.

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Surface oxide relationships to band bending in GaN

Cited by 48 publications

References 27 publications

Recombination of free and bound excitons in GaN

Recombination of free and bound excitons in GaN

Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

Modification of the N bonding environment in GaN after high-dose Si implantation: An x-ray absorption study

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