Direct Evidence of Drift-Assisted Carrier Transportation in a Gradient-Doped GaAs Photocathode

Zhou, Rui; Jani, Hemang; Duan, Lingze

doi:10.1364/cleo_at.2020.jw2f.35

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…This global exponential term can be viewed effectively as a descending exponential envelope propagating at a speed of 1 2 v d toward the device surface (i.e., the -x direction). It is the embodiment of the so-called drift-assisted carrier transportation 24 , which accelerates the accumulation of photoelectrons on the device surface.…”

Section: N(xt) Ementioning

confidence: 99%

Photoelectron Transportation Dynamics in GaAs Photocathodes

Zhou,

Jani,

Zhang

et al. 2021

Preprint

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We report here a general theory describing photoelectron transportation dynamics in GaAs semiconductor photocathodes. Gradient doping is incorporated in the model through the inclusion of directional carrier drift. The time-evolution of electron concentration in the active layer upon the injection of an excitation pulse is solved both numerically and analytically. The predictions of the model are compared with experiments via carrier-induced transient reflectivity change, which is measured for gradient-doped and uniform-doped photocathodes using femtosecond pump-probe reflectometry. Excellent agreement is found between the experiments and the theory, leading to the characterization of key device parameters such as diffusion constant and electron decay rates. Comparisons are also made between uniform doping and gradient doping for their characteristics in photoelectron transportation. Doping gradient is found to be able to accelerate electron accumulation on the device surface. These results offer new insights into the dynamics of III-V photocathodes and potentially open a new avenue toward experimental characterization of device parameters.

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Section: N(xt) Ementioning

confidence: 99%

Photoelectron Transportation Dynamics in GaAs Photocathodes

Zhou,

Jani,

Zhang

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Photoelectron transportation dynamics in GaAs photocathodes

Zhou

Jani

Zhang

et al. 2021

Journal of Applied Physics

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We report here a general theory describing photoelectron transportation dynamics in GaAs semiconductor photocathodes. Gradient doping is incorporated into the model through the inclusion of directional carrier drift. The time-evolution of electron concentration in the active layer upon the injection of an excitation pulse is solved both numerically and analytically. The predictions of the model are compared with experiments via a carrier-induced transient reflectivity change, which is measured for gradient-doped and uniform-doped photocathodes using femtosecond pump–probe reflectometry. An excellent agreement is found between the experiments and the theory, leading to the characterization of key device parameters, such as diffusion constant and electron decay rates. Comparisons are also made between uniform doping and gradient doping for their characteristics in photoelectron transportation. Doping gradient is found to be able to accelerate electron accumulation on the device surface. These results offer new insights into the dynamics of III–V photocathodes and potentially open a new avenue toward experimental characterization of device parameters.

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Evaluation of photocathode materials in combination with commercial fiber-coupled UV photon sources as a compact electron source in mass spectrometry

Münst,

Barwa,

Beyer

2024

Phys. Scr.

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The design of a compact electron source for mass spectrometry applications based on commercially available plug-and-play light sources and sturdy materials is presented, and its performance of photo-electron production is evaluated. We report quantum yields ranging between 1 – 2.5 x10-5 for aluminum, 9 x10-8 – 3 x10-6 for stainless steel, 1 – 2.2 x10-6 for molybdenum, 6.3 x10-7 – 5.1 x10-6 for tantalum, and 1.4 – 2.1 x10-6 for titanium, depending on the wavelength range of the irradiation source. In terms of quantum yield, the deuterium lamp provided better results compared to the two UV LEDs for all metals. However, due to their higher optical output power, the LEDs nevertheless yield a higher photoelectron current for all metals except for stainless steel. The measured photo-currents ranged from 1 – 2 nA for aluminum to 0.01 nA for Stainless Steel samples.

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Direct Evidence of Drift-Assisted Carrier Transportation in a Gradient-Doped GaAs Photocathode

Cited by 3 publications

References 10 publications

Photoelectron Transportation Dynamics in GaAs Photocathodes

Photoelectron Transportation Dynamics in GaAs Photocathodes

Photoelectron transportation dynamics in GaAs photocathodes

Evaluation of photocathode materials in combination with commercial fiber-coupled UV photon sources as a compact electron source in mass spectrometry

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