Pulse response of thin III/V semiconductor photocathodes

Aulenbacher, K.; Schuler, J.; Harrach, D. von; Reichert, E.; Röthgen, J.; Subashev, A.; Tioukine, V.; Yashin, Yu. P.

doi:10.1063/1.1521526

Cited by 75 publications

(36 citation statements)

References 16 publications

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“…In practice, band-bending can be incorporated into this model by redefining S 1;recombination as an effective recombination velocity at the interface between the low-field bulk and the bandbending region. [23][24][25] At the back surface (surface 2 in Fig. 1(b)), we assume that electrons cannot be emitted due to the presence of a substrate, and the recombination current J 2 is…”

Section: Derivation Of Emission Yieldmentioning

confidence: 99%

A model for emission yield from planar photocathodes based on photon-enhanced thermionic emission or negative-electron-affinity photoemission

Sahasrabuddhe

Schwede

Bargatin

et al. 2012

Journal of Applied Physics

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A general model is presented for electron emission yield from planar photocathodes that accounts for arbitrary cathode thickness and finite recombination velocities at both front and back surfaces. This treatment is applicable to negative electron affinity emitters as well as positive electron affinity cathodes, which have been predicted to be useful for energy conversion. The emission model is based on a simple one-dimensional steady-state diffusion treatment. The resulting relation for electron yield is used to model emission from thinfilm cathodes with material parameters similar to GaAs. Cathode thickness and recombination at the emissive surface are found to strongly affect emission yield from cathodes, yet the magnitude of the effect greatly depends upon the emission mechanism. A predictable optimal film thickness is found from a balance between optical absorption, surface recombination, and emission rate. Disciplines Mechanical EngineeringComments Sahasrabuddhe, K., Schwede, J., Bargatin, I., Jean, J., Howe, R., Shen, Z., & Melosh, N. (2012). A model for emission yield from planar photocathodes based on photon-enhanced thermionic emission or negativeelectron-affinity photoemission. Journal of Applied Physics, 112(9) A general model is presented for electron emission yield from planar photocathodes that accounts for arbitrary cathode thickness and finite recombination velocities at both front and back surfaces. This treatment is applicable to negative electron affinity emitters as well as positive electron affinity cathodes, which have been predicted to be useful for energy conversion. The emission model is based on a simple one-dimensional steady-state diffusion treatment. The resulting relation for electron yield is used to model emission from thin-film cathodes with material parameters similar to GaAs. Cathode thickness and recombination at the emissive surface are found to strongly affect emission yield from cathodes, yet the magnitude of the effect greatly depends upon the emission mechanism. A predictable optimal film thickness is found from a balance between optical absorption, surface recombination, and emission rate.

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Section: Derivation Of Emission Yieldmentioning

confidence: 99%

A model for emission yield from planar photocathodes based on photon-enhanced thermionic emission or negative-electron-affinity photoemission

Sahasrabuddhe

Schwede

Bargatin

et al. 2012

Journal of Applied Physics

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“…Time and energy-resolved experimental studies of the polarized photoemission give the estimates of these effects. Though the polarization losses in transport are not dominating, the mechanisms and relative contributions of the depolarization at these stages are still under debates [8]. The set of wavefunctions and the SL band spectra obtained here are prerequisites for calculations of the transport and spin relaxation parameters.…”

Section: Discussionmentioning

confidence: 99%

“…However, experimentally obtained values of the emitted electron polarization for unstrained SLs are typically less than 80 %. Since experimental studies of the electron depolarization in transport to the surface and emission in vacuum do not give more than 10 % depolarization for high quality thinlayer structures [8], the initial electron polarization becomes an important issue.…”

Section: Introductionmentioning

confidence: 99%

Optical spin orientation in strained superlattices

Subashiev

Gerchikov

Ipatov

2004

Journal of Applied Physics

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Optical orientation in the strained semiconductor superlattices is investigated theoretically. The dependence of the features in spinpolarization spectra on the structure parameters is clarified. The value of polarization in the first polarization maximum in the SL structures is shown to grow with the splitting between the hh-and lh-states of the valence band, the joint strain and confinement effects on the hh1-lh1 splitting being strongly influenced by the tunneling in the barriers. In strained structures with high barriers for the holes initial polarization can exceed 95 %. Calculated polarization spectra are close to the experimental spectra of polarized electron emission.

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“…The average photoemission time for a 100-nm thick strained GaAs cathode has been measured to be <τ> ~ 3 ps [3]. A spin-relaxation time shorter than about 50 ps would have a significant effect on polarization.…”

Section: Spin-relaxation and Ingap/gaas Superlatticementioning

confidence: 99%