Valence-band discontinuity between GaN and AlN measured by x-ray photoemission spectroscopy

Martin, G.; Strite, S.; Botchkarev, A.; Agarwal, Anchal; Rockett, Angus; Morkoç̌, H.; Lambrecht, Walter R. L.; Segall, B.

doi:10.1063/1.112247

Cited by 221 publications

(95 citation statements)

References 13 publications

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“…However, band offset parameters (Junction type: valence band offset (VBO)-DE v and conduction band offset (CBO)-DE c ) are measured for various heterojunctions in the literature, such as InN/GaN (Type-I: 0.58 6 0.08 and 2.22 6 0.1 eV), 14 GaN/ AlN (Type-I: 0.8 6 0.3 and %1.6 eV), 15 InN/AlN (Type-I: 1.52 6 0.17 and 4.00 6 0.2 eV), 16 InN/p-Si (Type-III: 1.39 and 1.81 eV), 17 ZnO/GaN (Type-II: 0.7 and 0.8 eV), 18 and MoS 2 /WSe 2 (Type-II: 0.83 and 0.76 eV). 19 To date there is no experimental report on the determination of band offset parameters (DE v and DE c ) and type of heterojunction by highresolution X-ray photoelectron spectroscopy (HRXPS) for epitaxially formed GaN/SL-MoS 2 heterojunction.…”

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confidence: 99%

Determination of band offsets at GaN/single-layer MoS2 heterojunction

Tangi

Mishra

et al. 2016

Applied Physics Letters

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We report the band alignment parameters of the GaN/single-layer (SL) MoS2 heterostructure where the GaN thin layer is grown by molecular beam epitaxy on CVD deposited SL-MoS2/c-sapphire. We confirm that the MoS2 is an SL by measuring the separation and position of room temperature micro-Raman E12g and A1g modes, absorbance, and micro-photoluminescence bandgap studies. This is in good agreement with HRTEM cross-sectional analysis. The determination of band offset parameters at the GaN/SL-MoS2 heterojunction is carried out by high-resolution X-ray photoelectron spectroscopy accompanying with electronic bandgap values of SL-MoS2 and GaN. The valence band and conduction band offset values are, respectively, measured to be 1.86 ± 0.08 and 0.56 ± 0.1 eV with type II band alignment. The determination of these unprecedented band offset parameters opens up a way to integrate 3D group III nitride materials with 2D transition metal dichalcogenide layers for designing and modeling of their heterojunction based electronic and photonic devices.

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confidence: 99%

Determination of band offsets at GaN/single-layer MoS2 heterojunction

Tangi

Mishra

et al. 2016

Applied Physics Letters

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“…12 The following material parameters were used: The band gap of Al x Ga 1Ϫx N at room temperature given by E g (x) ϭx6.2 eVϩ(1Ϫx)3.4 eVϪx(1Ϫx)1.0 eV, conductionband offset ⌬E C ϭ0.7͓E g (x)ϪE g (0)͔, 13,14 and dielectric constant ⑀ r (x)ϭ8.9Ϫ0.4x. 15,16 The effect of exchange correlation on Coulomb interaction was neglected, as this has been shown not to affect sheet carrier densities in AlGaN/ GaN heterostructures.…”

Section: Methodsmentioning

confidence: 99%

Polarization effects in AlGaN/GaN and GaN/AlGaN/GaN heterostructures

Heikman

Keller

et al. 2003

Journal of Applied Physics

208

130

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The influence of AlGaN and GaN cap layer thickness on Hall sheet carrier density and mobility was investigated for Al 0.32 Ga 0.68 N/GaN and GaN/Al 0.32 Ga 0.68 N/GaN heterostructures deposited on sapphire substrates. The sheet carrier density was found to increase and saturate with the AlGaN layer thickness, while for the GaN-capped structures it decreased and saturated with the GaN cap layer thickness. A relatively close fit was achieved between the measured data and two-dimensional electron gas densities predicted from simulations of the band diagrams. The simulations also indicated the presence of a two-dimensional hole gas at the upper interface of GaN/AlGaN/GaN structures with sufficiently thick GaN cap layers. A surface Fermi-level pinning position of 1.7 eV for AlGaN and 0.9-1.0 eV for GaN, and an interface polarization charge density of 1.6 ϫ10 13 -1.7ϫ10 13 cm Ϫ2 , were extracted from the simulations.

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“…The supposed band offset at the AlGaN/GaN interface was 70% of the bandgap discontinuity. 43,44 The estimated influence of temperature on the band offset and the spontaneous and piezoelectric polarization at the Al 0.25 Ga 0.75 N / GaN interface 36,41,43,[45][46][47][48][49] is negligible in the first approximation. Quantum corrections to the C-V curves are also unnecessary in the studied case.…”

Section: Polarization Chargementioning

confidence: 99%

Effects of interface states and temperature on the C-V behavior of metal/insulator/AlGaN/GaN heterostructure capacitors

Miczek

Mizue

Hashizume

et al. 2008

Journal of Applied Physics

179

141

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The impact of states at the insulator/AlGaN interface on the capacitance-voltage ͑C-V͒ characteristics of a metal/insulator/AlGaN/GaN heterostructure ͑MISH͒ capacitor was examined using a numerical solver of a Poisson equation and taking into account the electron emission rate from the interface states. A parallel shift of the theoretical C-V curves, instead of the typical change in their slope, was found for a MISH device with a 25-nm-thick AlGaN layer when the SiN x / AlGaN interface state density D it ͑E͒ was increased. We attribute this behavior to the position of the Fermi level at the SiN x / AlGaN interface below the AlGaN valence band maximum when the gate bias is near the threshold voltage and to the insensitivity of the deep interface traps to the gate voltage due to a low emission rate. A typical stretch out of the theoretical C-V curve was obtained only for a MISH structure with a very thin AlGaN layer at 300°C. We analyzed the experimental C-V characteristics from a SiN x / Al 2 O 3 / AlGaN/ GaN structure measured at room temperature and 300°C, and extracted a part of D it ͑E͒. The relatively low D it ͑ϳ10 11 eV −1 cm −2 ͒ in the upper bandgap indicates that the SiN x / Al 2 O 3 bilayer is applicable as a gate insulator and as an AlGaN surface passivant in high-temperature, high-power AlGaN/GaN-based devices.

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Valence-band discontinuity between GaN and AlN measured by x-ray photoemission spectroscopy

Cited by 221 publications

References 13 publications

Determination of band offsets at GaN/single-layer MoS2 heterojunction

Determination of band offsets at GaN/single-layer MoS2 heterojunction

Polarization effects in AlGaN/GaN and GaN/AlGaN/GaN heterostructures

Effects of interface states and temperature on the C-V behavior of metal/insulator/AlGaN/GaN heterostructure capacitors

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