Compensation mechanisms in GaAs

Martin, G. M.; Farges, J.; Jacob, Guy; Hallais, J.; Poiblaud, G.

doi:10.1063/1.327952

Cited by 322 publications

(53 citation statements)

References 21 publications

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“…Different compensation mechanisms were developed in the analyses of the experimental data. It was, however, a priori assumed that the material is semi-insulating in the calculations of the Fermi level (6,7). Recently, a multilevel model without any a electron.…”

Section: Introductionmentioning

confidence: 99%

Deep levels in semiconductors

Lombos¹

1985

Can. J. Chem.

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This paper is dedicated to Professor Camille Sandorb on the occasion of his 65th birthdayB. A. LOMBOS. Can. J. Chem. 63, 1666 (1985.The role of deep-lying trapping centers in semi-insulating GaAs, polysilicon and polycrystalline tin oxide transparent electrode has been systematically investigated. It was demonstrated that some of the peculiar transport properties of these semiconductors can be elucidated by deep level compensation. A multilevel model is presented to determine the position of the Fermi level as a function of impurity concentrations. These include, quantitatively, the deep-lying levels which have been introduced by doping in the case of GaAs and by grain boundaries in the case of polycrystalline films. In the latter cases the dangling bonds, associated to lattice defects, are characterized by energy levels which are localized in the energy gap. These dangling bonds can act as electron traps when empty and hole traps when occupied. These are the deep levels.In each of the investigated three cases, this concept permitted the elucidation of some of the transport properties of these semiconductors. B. A. LOMBOS. Can. J . Chem. 63, 1666 (1985 On a CtudiC d'une faqon systkmatique le r81e des centres profonds de piegeage dans le GaAs semi-isolant, dans le polysilicium et dans une tlectrode transparente d'oxyde d'Ctain polycristallin. On dCmontre que I'on peut Clucider quelques unes des propriCtCs particulieres de transport de ces semi-conducteurs en faisant appel 2 une compensation par des niveaux profonds. On prCsente un modkle h plusieurs niveaux pour determiner la position du niveau de Fermi en fonction des concentrations des impuretCs. Ceux-ci comprennent quantitativernent les niveaux profonds que I'on a introduit par dopage dans le cas du GaAs et par les joints des grains dans le cas des films polycristallins. Dans ces derniers cas, les liaisons pendantes associCes aux dCfauts du rCseau sont associees h des niveaux dlCnergie qui sont localises dans la bande interdite. Ces liaisons pendantes peuvent agir comrne piege d'Clectrons quand elles sont vides et cornrne piege de trous lorsqu'elles sont occupCes. Ce sont les niveaux profonds.Dans chacun des trois cas CtudiCs, ce concept perrnet dlClucider certaines propriCtCs de transport de ces semi-conducteurs.[Traduit par le journal] Introduction The role of deep-lying impurity levels in semiconductors became important with the discovery of semi-insulating GaAs (SI GaAs) (1). This modification of the normally semiconducting GaAs resulted in the possibility of the realization of a number of solid state devices and integrated circuits by epitaxial technology. Due to the inherent electrical properties of GaAs, superior to those of silicon and germanium, the wellknown classical active materials for the microelectronic industry, GaAs components have improved properties. These include their high frequency response, high temperature or power handling capacity, radiation hardness for satellite electronics, and the possibility for optoelectronic applications, such ...

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Section: Introductionmentioning

confidence: 99%

Deep levels in semiconductors

Lombos¹

1985

Can. J. Chem.

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“…The two pump pulses were focused to a spot of 65 µm diameter with total fluence 3.0 µJ/cm 2 except as indicated; probe pulses were always a factor of 2.5 weaker. Assuming one photoexcited electron per absorbed photon in a 1 µm absorption length 10 , we photoexcite ∼ 8.5 × 10 16 cm −3 carriers, greater than the typical concentration of deep traps in SI-GaAs 11 . In this way we are able to measure motion of free carriers at times longer than the trapping time, and to use the density of photoexcited electrons as an estimate of the free-carrier density.…”

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confidence: 99%

Measurement of spin diffusion in semi-insulating GaAs

Weber

Benko

Hiew

2011

Journal of Applied Physics

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We use optical transient-grating spectroscopy to measure spin diffusion of optically oriented electrons in bulk, semi-insulating GaAs(100). Trapping and recombination do not quickly deplete the photoexcited population. The spin diffusion coefficient of 88 ± 12 cm 2 /s is roughly constant at temperatures from 15 K to 150 K, and the spin diffusion length is at least 450 nm. We show that it is possible to use spin diffusion to estimate the electron diffusion coefficient. Due to electron-electron interactions, the electron diffusion is 1.4 times larger than the spin diffusion. The burgeoning field of semiconductor spintronics relies on moving spin-polarized electrons through distances comparable to the dimensions of an electronic device. The importance of spin transport has led to several studies of spin diffusion in GaAs quantum wells. Spin transport in quantum wells can differ markedly from the bulk material, due to to different scattering rates and especially to the different spin-orbit coupling 1 . Nonetheless, there have been relatively few measurements 2-4 of spin diffusion in bulk GaAs. In n-doped samples with n = 1 × 10 16 and 2 × 10 16 cm −3 , the spin diffusion coefficient D s ranged from 10 to 200 cm 2 /s. Spin diffusion in semi-insulating GaAs (SI-GaAs) has not been reported. SI-GaAs has been proposed as a platform for nuclear spintronics 5 due to its low carrier density. Moreover, Kikkawa et al. showed that electrons could be optically oriented in SI-GaAs and would subsequently diffuse into an adjacent ZnSe film, maintaining their spin polarization 6 . Since SI-GaAs is a ubiquitous substrate material for thin film growth and for spintronic devices, such spin diffusion is of practical consequence, whether intentional or not. In this work, we find that SI-GaAs has a large, temperature-independent spin diffusion coefficient.We measured spin diffusion with an ultrafast transient spin grating 7 , which measures the decay rate γ s of a spin-density wave (the "grating") with wavelength Λ and wavevector q = 2π/Λ. The grating amplitude decays-through spin relaxation, electron-hole recombination, and diffusion-at a rate of Here, D s is the spin diffusion coefficient, and τ 0 is the lifetime for trapping, recombination, and spin relaxation. Measurement at several q determines D s . We measure in a reflection geometry, and improve the detection efficiency by heterodyne detection 8 . Noise is further suppressed by 95 Hz modulation of the grating phase and lock-in detection 9 . The SI-GaAs sample was grown by Wafer Technology. It was undoped, oriented (100), had room temperature resistivity ρ ≥ 107 Ω-cm and Hall mobility µ H ≥ 5000 cm 2 /V-s. The pump and probe pulses came from a mode-locked Ti:Sapphire laser with wavelength near 800 nm and repetition rate of 80 MHz. The two pump pulses were focused to a spot of 65 µm diameter with total fluence 3.0 µJ/cm 2 except as indicated; probe pulses were always a factor of 2.5 weaker. Assuming one photoexcited electron per absorbed photon in a 1 µm absorption length 10 , we p...

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“…By control of the incorporation of carbon into the melt during crystal growth carrier concentration and resistivity of the crystal can be adjusted. If the above-mentioned conditions are fulfilled, the dependence of carrier concentration n from carbon content N C can be calculated for a given EL2 concentration N EL2 by the approximation [2] ( )…”

Section: Introductionmentioning

confidence: 99%

“…where N CB is the density of states in the conduction band and E EL2 the ionisation energy of EL2 (0.69 eV at 300 K [2]). The concentration of carbon can be determined by local vibrational mode (LVM) spectroscopy [3,4] and the concentration of EL2 by absorption measurements in the near infrared [5].…”

Section: Introductionmentioning

confidence: 99%

Influence of compensation level on EL2 concentration in semi‐insulating gallium arsenide

Kretzer

Alt

2003

phys. stat. sol. (c)

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The concentration of the intrinsic mid-gap donor EL2 in semi-insulating GaAs is known to be dependent on melt composition during crystal growth and on post-growth thermal treatment of crystals. A detailed analysis of data emerged from monitoring the production process of state-of-the-art GaAs substrates revealed discrepancies to the compensation model. By means of a combination of methods for quantitative point defect analysis we can show that EL2 concentration depends also on compensation ratio or position of Fermi level, respectively.

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Compensation mechanisms in GaAs

Cited by 322 publications

References 21 publications

Deep levels in semiconductors

Deep levels in semiconductors

Measurement of spin diffusion in semi-insulating GaAs

Influence of compensation level on EL2 concentration in semi‐insulating gallium arsenide

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