Identification of a second energy level of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>EL</mml:mi><mml:mn>2</mml:mn><mml:mn /></mml:math>in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-type GaAs

Omling, P.; Silverberg, P.; Samuelson, Lars

doi:10.1103/physrevb.38.3606

Cited by 32 publications

(9 citation statements)

References 11 publications

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“…The EL2 center is the best characterized defect in GaAs, with a number of fascinating, distinctive and well-defined properties [36]. The EL2 is a double donor, with the first donor level near midgap, E c − 0.75 eV, and a second donor level ∼0.3 eV below that [37], at E v + 0.54 eV [38,39]. At low temperatures, the neutral EL2 can be optically bleached, transform into a metastable EL2 * state, rendering the defect electrically invisible.…”

Section: Defect Resultsmentioning

confidence: 99%

Simple intrinsic defects in gallium arsenide

Schultz¹,

Lilienfeld²

2009

Modelling Simul. Mater. Sci. Eng.

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We investigate the structural properties and energy levels of simple intrinsic defects in gallium arsenide. The first-principles calculations (1) apply boundary conditions appropriate to charge defects in supercells and enable quantitatively accurate predictions of defect charge transitions with a supercell approximation, (2) are demonstrated to be converged with respect to cell size and (3) assess the sensitivity to model construction to Ga pseudopotential construction (3d core or 3d valence) and density functionals (local density or generalized gradient approximation). With these factors controlled, we present the first quantitatively reliable survey of defect levels in GaAs, reassess the available literature and begin to decipher the complexity of GaAs defect chemistry. The computed defect level spectrum spans the experimental GaAs band gap, defects exhibit multiple bistabilities with (sometimes overlapping) negative-U systems, express more extensive charge states than previously anticipated and collectively suggest that our atomistic understanding of GaAs defect physics needs to be reassessed.

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Section: Defect Resultsmentioning

confidence: 99%

Simple intrinsic defects in gallium arsenide

Schultz¹,

Lilienfeld²

2009

Modelling Simul. Mater. Sci. Eng.

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“…17͒ and the second optical ionization of As Ga ϩ . 18 Consequently, we attribute the excess linear absorption in as-grown GaAs to the As Ga 0 -CB transition. We refer to the As Ga 0 -CB absorption as to ␣ T , given by ␣ T ϭ␣ lin Ϫ␣ lin ͑HT͒ ͓␣ lin ͑HT͒ linear absorption in standard, high-temperature GaAs͔.…”

mentioning

confidence: 94%

Optical nonlinearity in low-temperature-grown GaAs: Microscopic limitations and optimization strategies

Haiml

Siegner

Morier‐Genoud

et al. 1999

Applied Physics Letters

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We have quantitatively measured the linear and the nonsaturable absorption as well as the absorption modulation and its recovery time in as-grown and annealed low-temperature (LT) GaAs. Correlation of the optical data with As antisite (AsGa) defect densities yields the absorption cross section and the saturation parameter of the dominant AsGa to the conduction-band defect transition. We show that this defect transition is mainly responsible for the large nonsaturable absorption in as-grown LT GaAs with fast recovery times. Reducing the AsGa density by annealing yields an optimized material with small nonsaturable absorption, high absorption modulation, and fast recovery times.

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“…This is because ion implantation into GaAs generates As antisites. 18 These defect states are located close to the center of the band gap 19 and pin the Fermi level at midgap. 20 Since the Fermi level in the unimplanted regions is also at midgap in the undoped quantum well, we do not expect the formation of large potential gradients.…”

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confidence: 99%

Direct experimental observation of different diffusive transport regimes in semiconductor nanostructures

Achermann¹,

Nechay²,

Morier‐Genoud³

et al. 1999

Phys. Rev. B

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A near-field pump-probe system with nanometer-scale spatial and femtosecond temporal resolution allows us to measure complex spatiotemporal carrier diffusion dynamics in semiconductor nanostructures. Single GaAs/Al x Ga 1Ϫx As quantum wells are patterned by nanometer-scale focused ion-beam ͑FIB͒ implantation, which introduces local carrier trapping. The resulting carrier density gradients cause diffusion, which is directly observed by measuring carrier density variations in both time and space. A comprehensive experimental study allows us to identify different diffusion regimes. We find an initial diffusion regime, characterized by nonsinusoidal carrier profiles and spatially dependent temporal diffusion decay. In a long-time regime, the carrier profile is quasisinusoidal and only weakly position-dependent temporal diffusion decay is observed.

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Identification of a second energy level ofEL2inn-type GaAs

Cited by 32 publications

References 11 publications

Simple intrinsic defects in gallium arsenide

Simple intrinsic defects in gallium arsenide

Optical nonlinearity in low-temperature-grown GaAs: Microscopic limitations and optimization strategies

Direct experimental observation of different diffusive transport regimes in semiconductor nanostructures

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