Properties of metal-insulator transition and electron spin relaxation in GaN:Si

Wołoś, Agnieszka; Wilamowski, Ż.; Piersa, M.; Strupiński, Włodek; Łucznik, B.; Grzegory, I.; Porowski, S.

doi:10.1103/physrevb.83.165206

Cited by 35 publications

(41 citation statements)

References 26 publications

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“…These estimated values are well above the MIT for n-type GaN:Si of 1.6 × 10 18 cm −3 [31] and theoretical predictions for h-GaN of 1 × 10 18 cm −3 [32]. The 14 N spectrum of GaN:Ge in Figure 1(b) corroborates and extends these conclusions.…”

Section: Fig 2 (Color Online) (A)supporting

confidence: 81%

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: Fig 2 (Color Online) (A)supporting

confidence: 81%

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

et al. 2017

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“…34 In a previous study 18 , the g-values were found to be unchanged (within the experimental errors of ∆g=0.0007) in the temperature range of 5-300 K. Our observed increase of the g-value with increasing temperature is similar to the observation in Ref. 17.…”

Section: B Delocalized Donor Electrons and Formation Of Impurity Bandssupporting

confidence: 78%

Electronic properties of the residual donor in unintentionally doped β-Ga2O3

Són

Goto

Nomura

et al. 2016

Journal of Applied Physics

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Electron paramagnetic resonance (EPR) was used to study the donor that is responsible for the n-type conductivity in unintentionally doped (UID) β-Ga2O3 substrates. We show that in asgrown material, the donor requires high temperature annealing to be activated. In partly activated material with the donor concentration in the 10 16 cm -3 range or lower, the donor is found to behave as a negative-U center (often called a DX center) with the negative charge

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“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 correspond to NW length and radius of NID GaN NWs; (g) NW radius variation with the height of the NW, measured along the dashed line in (e). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 determined by Hall measurements for GaN epilayers with different Si doping levels (carrier concentration is designated close to the corresponding line, with a unit of 10 18 cm -3 ) 39 , and the gray dashed line stands for high conducting Si-doped GaN microwire previously reported …”

Section: Notesmentioning

confidence: 99%

Si Donor Incorporation in GaN Nanowires

et al. 2015

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With increasing interest in GaN based devices, the control and evaluation of doping are becoming more and more important. We have studied the structural and electrical properties of a series of Si-doped GaN nanowires (NWs) grown by molecular beam epitaxy (MBE) with a typical dimension of 2-3 μm in length and 20-200 nm in radius. In particular, high resolution energy dispersive X-ray spectroscopy (EDX) has illustrated a higher Si incorporation in NWs than that in two-dimensional (2D) layers and Si segregation at the edge of the NW with the highest doping. Moreover, direct transport measurements on single NWs have shown a controlled doping with resistivity from 10(2) to 10(-3) Ω·cm, and a carrier concentration from 10(17) to 10(20) cm(-3). Field effect transistor (FET) measurements combined with finite element simulation by NextNano(3) software have put in evidence the high mobility of carriers in the nonintentionally doped (NID) NWs.

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Properties of metal-insulator transition and electron spin relaxation in GaN:Si

Cited by 35 publications

References 26 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

Electronic properties of the residual donor in unintentionally doped β-Ga2O3

Si Donor Incorporation in GaN Nanowires

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