Theoretical investigation of the dynamic process of the illumination of GaAs

Ren, Guina; Wang, Zhanguo; Xu, Bo; Zhou, Bing

doi:10.1103/physrevb.50.5189

Cited by 3 publications

(2 citation statements)

References 21 publications

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“…We get good agreement with only one adjustable parameter, C 1 , determining the shape of the theoretical curve ͑C 2 is just a multiplicative factor͒. The value obtained from data fitting for C 1 =2ϫ 10 −17 s cm 3 is within an order of magnitude of the value computed from the literature, 16 3 ϫ 10 −18 s cm 3 . The present model predicts the peak just below the band gap as well as the dip at ϳ1.52 eV due to strong exciton absorption.…”

Section: Excitation and Recombination Modelsupporting

confidence: 79%

Penetration depth model for optical alignment of nuclear spins in GaAs

Coles

Reimer

2007

Phys. Rev. B

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A framework for predicting bulk NMR quantities in semi-insulating GaAs under optical alignment conditions is developed by combining literature penetration depth data with simple kinetic equations. The model accounts for the major photoconductivity and NMR intensity variations with photon energy, including the peak near 1.5 eV. With the fitting parameters fixed, the photon-flux dependence of the NMR intensity is predicted quantitatively up to an energy shift. At the highest fluxes, we see the NMR intensity level off, suggesting that it is possible to completely fill the relevant electronic reservoir. The model also quantitatively fits the time dependence of the light-induced hyperfine shift. The experimental and modeling results have implications toward understanding the microscopic mechanism, and are consistent with nuclear polarization via bound electrons. Finally, the model makes experimentally testable predictions for the photon energy and flux dependences of the spin temperature and hyperfine shift of the NMR line.

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Section: Excitation and Recombination Modelsupporting

confidence: 79%

Penetration depth model for optical alignment of nuclear spins in GaAs

Coles

Reimer

2007

Phys. Rev. B

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“…The carrier lifetime is reduced for increasing temperatures, and therefore it is more difficult to detect them at the high temperature limit. The carrier lifetime is related to EL2 ͑or to EL2-like͒ density by ϭ͓C n (T)N t ͔ Ϫ1 , where C n (T) is the recombination rate of the free electrons in the conduction band to the EL2 ͑or to EL2-like͒ centers, 17 and N t is the defect concentration. At 150 K we have found for sample BH2 a carrier lifetime around 45 ps for this transition.…”

Section: Resultsmentioning

confidence: 99%

Thermally stimulated current spectroscopy on silicon planar-doped GaAs samples

Rubinger

Bezerra

Chagas

et al. 1998

Journal of Applied Physics

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Using thermally stimulated current ͑TSC͒ spectroscopy we have identified the presence of several deep traps in low temperature grown ͑LTG͒ nonintentionally doped bulk molecular beam epitaxy ͑MBE͒-GaAs and silicon planar-doped MBE-GaAs samples. The experiments of TSC spectroscopy were carried out on a LTG MBE-GaAs epilayer grown at 300°C and the planar-doped layer with a nominal silicon concentration of 3.4ϫ10 12 cm Ϫ2 . The LTG nonintentionally doped bulk MBE-GaAs sample shows three peaks in the TSC spectra but the planar-doped MBE-GaAs sample shows spectra similar to those of bulk samples grown by the liquid-encapsulated Czochralski and vertical gradient freeze methods. The main achievement is the experimental evidence that the potential well present in the planar-doped sample is effective in detecting the presence of different deep traps previously not seen in LTG bulk MBE-GaAs epilayers due to a shorter carrier lifetime ͑about 10 Ϫ12 s) in the conduction band which occurs due to EL2-like deep traps recombination. This fact is evidenced by a strong hopping conduction in LTG bulk MBE-GaAs samples at temperatures lower than 300 K, but not in planar-doped MBE-GaAs samples because the two-dimensional electron gas has a higher mobility than lateral LTG bulk MBE-GaAs epilayers.

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Nuclear hyperpolarization in solids and the prospects for nuclear spintronics

Reimer

2010

Solid State Nuclear Magnetic Resonance

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Theoretical investigation of the dynamic process of the illumination of GaAs

Cited by 3 publications

References 21 publications

Penetration depth model for optical alignment of nuclear spins in GaAs

Penetration depth model for optical alignment of nuclear spins in GaAs

Thermally stimulated current spectroscopy on silicon planar-doped GaAs samples

Nuclear hyperpolarization in solids and the prospects for nuclear spintronics

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