Air stabilized (001) <i>p</i>-type GaAs fabricated by molecular beam epitaxy with reduced surface state density

The influence of ionized impurity scattering on the hole mobility in ␦-doped-channel AlGaAs-InGaAs quantum wells is investigated. Improvements by a factor of 2.5 were observed experimentally when moving a ␦-doped impurity plane across the quantum well towards an interface, highlighting the scope of selective doping and wave-function engineering techniques to enhance the transport mobility of such devices. Theoretical hole mobility calculations were performed and reveal an overestimation of the transport mobility, common to the random-phase approximation ͑RPA͒, that is much stronger for p-type structures than for n-type structures. This effect is partially attributed to an underestimation of the screening charge distribution width. Using a lower limit for this distribution of around 50 Å, it is shown that the RPA can provide accurate predictions between samples with different impurity distributions and densities.

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“…The latter value, which is not critical for the wide barriers as used in this work, is in qualitative agreement with Ref. 13.…”

Section: A Scps Calculationssupporting

confidence: 78%

Theoretical and experimental investigation of doped-channelp-type quantum wells

et al. 2000

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“…10,15,16 Although GaAs MOS research started as early as in 1965 at the RCA laboratory, 17 there are just a few reports in literature addressing the fundamental surface chemistry and physics on the difficult type of GaAs substrates. [18][19][20][21] Pashley et al applied scanning tunnel microscopy to characterize the electronic properties of MBE grown GaAs ͑001͒ surfaces with ͑2 ϫ 4͒ / c͑2 ϫ 8͒ reconstructions in high vacuum and found that Fermi level in p-GaAs is located near the valence band edge, in contrast to the midgap Fermi-level pinning in n-GaAs case due to the high density of acceptorlike kink sites formed at the surface of n-GaAs. 20 Other experiments also indicate that p-GaAs has reduced surface state density, compared to n-GaAs, even after being exposed to air.…”

mentioning

confidence: 99%

“…Photochemical reactions on GaAs can explain why n-GaAs are oxidized easier than p-type GaAs. 21 For illuminated n-GaAs, the reaction is GaAs+ 6e + ↔ Ga 3+ +As 3+ , which leads to photo-oxidation, i.e., Ga and As oxides and elemental As. In illuminated p-GaAs, the electron minority carriers result in surface passivation and the reaction is GaAs +3e − ↔ Ga+ As 3− and As 3− +3H + ↔ AsH 3 ↑, which leads to preferential Ga oxide formation.…”

mentioning

confidence: 99%

“…20 Other experiments also indicate that p-GaAs has reduced surface state density, compared to n-GaAs, even after being exposed to air. 21 In order to understand this N-dispersion phenomenon with the current ex situ ALD process, we examine the composition of native oxides on n-type GaAs and p-type GaAs substrates by x-ray photoelectron spectroscopy ͑XPS͒, as shown in Figs. 2͑c͒ and 2͑d͒.…”

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confidence: 99%

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Interface studies of GaAs metal-oxide-semiconductor structures using atomic-layer-deposited HfO2∕Al2O3 nanolaminate gate dielectric

Yang

Xuan

Zemlyanov

et al. 2007

Applied Physics Letters

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A systematic capacitance-voltage study has been performed on GaAs metal-oxide-semiconductor (MOS) structures with atomic-layer-deposited HfO2∕Al2O3 nanolaminates as gate dielectrics. A HfO2∕Al2O3 nanolaminate gate dielectric improves the GaAs MOS characteristics such as dielectric constant, breakdown voltage, and frequency dispersion. A possible origin for the widely observed larger frequency dispersion on n-type GaAs than p-type GaAs is discussed. Further experiments show that the observed hysteresis is mainly from the mobile changes and traps induced by HfO2 in bulk oxide instead of those at oxide/GaAs interface.

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“…These densities are the lowest surface state densities found in similar semiconductor microstructures and are 1-2 orders of magnitude less than the surface state density required for the pinned surface of the surface Fermi level. 25 For each sample with specific undoped thickness d, the surface Fermi energy E f can be derived from Eqs. ͑4͒ and ͑5͒ while the occupied surface state density D s can be calculated from Eq.…”

Section: Resultsmentioning

confidence: 99%

Photoreflectance study of the surface state density and distribution function of InAlAs

Hwang

Chang

et al. 2001

Journal of Applied Physics

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Photoreflectance is used to investigate the band gap, built-in electric field, and surface Fermi level of a series of lattice-matched In0.52Al0.48As surface-intrinsic n+ structures having different undoped layer thicknesses. Experimental results indicate that, although the built-in electric field depends on the undoped layer thickness, there is a range of thickness within which the surface Fermi level is weakly pinned. From the dependence of electric field and surface Fermi level on the undoped layer thickness, we can determine that the surface states distribute over two separate regions within the energy band gap. The densities of the surface states are evaluated as well. Moreover, the dependence of the built-in electric field on undoped layer thickness is converted into the dependence of surface state density on the surface Fermi level in order to theoretically and exactly calculate the energy spectrum of the surface state density using a Guassian distribution function. The center and width of the distribution near the conduction band are obtained from the fitting parameters.

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Air stabilized (001) p-type GaAs fabricated by molecular beam epitaxy with reduced surface state density

Abstract: Articles you may be interested inPhotoluminescence investigation of GaInP/GaAs multiple quantum wells grown on (001) and (311) B GaAs surfaces by gas source molecular beam epitaxy

Cited by 24 publications

References 11 publications

Theoretical and experimental investigation of doped-channelp-type quantum wells

Theoretical and experimental investigation of doped-channelp-type quantum wells

Interface studies of GaAs metal-oxide-semiconductor structures using atomic-layer-deposited HfO2∕Al2O3 nanolaminate gate dielectric

Photoreflectance study of the surface state density and distribution function of InAlAs

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