Correlated Compositions, Structures, and Photoluminescence Properties of Gallium Nitride Nanoparticles

Schwenzer, Birgit; Hu, Jerry; Morse, Daniel E.

doi:10.1002/adma.201003750

Cited by 15 publications

(27 citation statements)

References 29 publications

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“…A recent modeling study based on hybrid functional calculations [54] predicted similar shallowdonor electronic behaviors for O N and Ge Ga substitution defects in GaN, which is fully consistent with our analyses of the similar NMR spectral features and corresponding electronic structures observed here for nanocrystalline GaN and bulk GaN:Ge. These results are also consistent with previous results [23] for nanocrystalline GaN synthesized differently, which exhibited a broad distribution of Knight-shifted intensities [39].…”

Section: Likely Shallow Donors In Nanocrystalline Gansupporting

confidence: 93%

“…are well above the MIT. Our results resolve widely differing interpretations of the electronic structure of nanocrystalline GaN powders manifested by their 69 Ga, 71 Ga and 15 N NMR spectra [14,[20][21][22][23][24][25][26]. The results also represent a detailed electronic structural characterization of a degenerately doped semiconductor in bulk and nanocrystalline forms.…”

Section: Introductionsupporting

confidence: 71%

“…71 Ga Knight shifts, but affecting a smaller proportion of Ga atoms, are observed for smaller-size GaN nanocrystals (8-11 nm) [22,23]. The 71 Ga NMR relaxation analyses establish conclusively that the nanocrystalline GaN is heavily doped above the MIT, and demonstrate that synthesis of nanocrystalline GaN by ammonolysis is an effective way to introduce electrically-active dopants into a semiconductor nanomaterial, which can otherwise be difficult [41].…”

Section: Oretical Line From Eq(3) Similar Distributions Ofmentioning

confidence: 73%

“…71 Ga MAS NMR results on similar GaN nanoparticle materials found little or no evidence for anisotropic second-order quadrupolar broadening effects across the Knight shift distribution [23]. Secondly, if such effects were responsible, then one would not expect Korringa-type relaxation behavior across the entire distribution of 71 Ga Knight shifts, as observed in Fig.…”

Section: Firstly Previousmentioning

confidence: 91%

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Spatially correlated distributions of local metallic properties in bulk and nanocrystalline GaN

et al. 2017

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We compare local electronic structure at different atom types of a metallic semiconductor in bulk and nanocrystalline form. Multinuclear magic-angle-spinning nuclear magnetic resonance (MAS NMR) establishes that GaN synthesized as an intentionally-doped bulk powder or as annealed nanocrystalline particles exhibits metallic behavior and a wide distribution of differing electronic environments in both forms. Bulk polycrystalline wurtzite GaN doped with 0.13% Ge as a shallow donor exhibits a temperature-independent distribution of 71 Ga Knight shifts over the temperature range 123-473 K. Each Knight shift frequency in the inhomogeneously-broadened spectrum is characterized by a 71 Ga spin-lattice relaxation time T 1 that is in good agreement with the value predicted by the Knight-Korringa relation across the broad range of temperatures. The14 N spectrum shows a slightly smaller Knight shift distribution with spin-lattice relaxation time T 1 values at 295 K across the distribution also in good agreement with the Knight-Korringa relation. Similarly, annealed nanocrystalline wurtzite GaN (50-100 nm, and without Ge) exhibits a 71 Ga Knight shift distribution and T 1values (at 295 K) that follow the same Knight-Korringa behavior. Thus, both bulk and nanocrystalline forms of GaN are n-type and well above the metal-insulator transition (MIT), the nanocrystals most likely as a result of incorporation of shallow donor oxygen atoms during synthesis. Carriers in both forms of sample exhibit the near-ideal characteristics of a degenerate Fermi gas of non-interacting spins. The observation of NMR signals from both atom types, Ga and N, allows for the direct spatial correlation of the local electronic structure at the two sites in the lattice, specifically the s-orbital character of the electronic wavefunction of conduction band electrons at the Fermi edge. The relative values of these carrier wavefunction probabilities (nearly twice as great for the N atom as for the Ga) are in line with theoretical predictions. Analyses of 71 Ga, 14 N, and 15 N NMR results, including double-resonance 2D 15 N{ 71 Ga} measurements, reveal electronic disorder in the form of broad distributions of local metallic properties (Knight shifts) that are shown to be spatially correlated on a sub-nanometer scale.

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Section: Likely Shallow Donors In Nanocrystalline Gansupporting

confidence: 93%

Section: Introductionsupporting

confidence: 71%

Section: Oretical Line From Eq(3) Similar Distributions Ofmentioning

confidence: 73%

Section: Firstly Previousmentioning

confidence: 91%

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Spatially correlated distributions of local metallic properties in bulk and nanocrystalline GaN

et al. 2017

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“…The NMR spectrum of the sample obtained at 900°C exhibited a narrow GaN peak with a shoulder on the lower field side. The shoulder can be explained by either a nitrogen deficiency in GaN 5),16), 17) or a Knight shift due to the presence of conduction electrons. 6), 18) Raman scattering of hexagonal GaN has been extensively studied in numerous works.…”

mentioning

confidence: 99%

Use of polymeric carbon nitride in the nitridation of gallium oxide to gallium nitride

Jung

2016

J. Ceram. Soc. Japan

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Gallium nitride (GaN) powder was prepared from ¢-gallium oxide (¢-Ga 2 O 3 ) powder using polymeric carbon nitride (PCN) as a nitridation reagent and characterized by powder X-ray diffraction, 71Ga magic-angle spinning nuclear magnetic resonance spectroscopy, Raman spectroscopy, and scanning electron microscopy. ¢-Ga 2 O 3 was completely nitridated to GaN at the temperature above 800°C. The change in the morphology after the nitridation can be explained by two successive reactions, i.e., the reduction of Ga 2 O 3 to gaseous Ga 2 O and its subsequent nitridation to GaN, with the rate of the former reaction being slower than that of the latter.

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Ammoniak‐in‐Öl‐Mikroemulsionen und deren Verwendung

et al. 2013

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Flüssiger Ammoniak auf der Nanoskala: Erstmals wird eine Ammoniak‐in‐Öl‐Mikroemulsion vorgestellt, die reproduzierbar und ebenso einfach wie eine konventionelle Wasser‐in‐Öl‐Mikroemulsion verwendet werden kann – mit Ausnahme der für flüssigen Ammoniak notwendigen geringen Temperatur von −40 °C. Als Konzeptstudie wurde die Synthese von Bi0‐, Re0‐, CoN‐ und GaN‐Nanopartikeln untersucht, und überraschenderweise sind unmittelbar kristalline Nanopartikel ohne weitere thermische Behandlung zugänglich.

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Correlated Compositions, Structures, and Photoluminescence Properties of Gallium Nitride Nanoparticles

Cited by 15 publications

References 29 publications

Spatially correlated distributions of local metallic properties in bulk and nanocrystalline GaN

Spatially correlated distributions of local metallic properties in bulk and nanocrystalline GaN

Use of polymeric carbon nitride in the nitridation of gallium oxide to gallium nitride

Ammoniak‐in‐Öl‐Mikroemulsionen und deren Verwendung

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