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Energy distribution and quantum yield for photoemission from air-contaminated gold surfaces under ultraviolet illumination close to the threshold

Hechenblaikner, Gerald and Ziegler, Tobias and Biswas, Indro and Seibel, Christoph and Schulze, Mathias and Brandt, Nico and Schöll, Achim and Bergner, Patrick and Reinert, Friedrich T. (2012) Energy distribution and quantum yield for photoemission from air-contaminated gold surfaces under ultraviolet illumination close to the threshold. Journal of Applied Physics, 111 (12), p. 124914. American Institute of Physics (AIP). DOI: 10.1063/1.4730638 ISSN 0021-8979

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Official URL: http://jap.aip.org/resource/1/japiau/v111/i12/p124914_s1

Abstract

The kinetic energy distributions of photo-electrons emitted from gold surfaces under illumination by UV-light close to the threshold (photon energy in the order of the material work function) are measured and analyzed. Samples are prepared as chemically clean through Ar-ion sputtering and then exposed to atmosphere for variable durations before quantum yield measurements are performed after evacuation. During measurements, the bias voltage applied to the sample is varied and the resulting emission current measured. Taking the derivative of the current-voltage curve yields the energy distribution which is found to closely resemble the distribution of total energies derived by DuBridge for emission from a free electron gas. We investigate the dependence of distribution shape and width on electrode geometry and contaminant substances adsorbed from the atmosphere, in particular, to water and hydro-carbons. Emission efficiency increases initially during air exposure before diminishing to zero on a timescale of several hours, whilst subsequent annealing of the sample restores emissivity. A model fit function, in good quantitative agreement with the measured data, is introduced which accounts for the experiment-specific electrode geometry and an energy dependent transmission coefficient. The impact of large patch potential fields from contact potential drops between sample and sample holder is investigated. The total quantum yield is split into bulk and surface contributions which are tested for their sensitivity to light incidence angle and polarization. Our results are directly applicable to model parameters for the contact-free discharge system onboard the Laser Interferometer Space Antenna (LISA) Pathfinder spacecraft.

Item URL in elib:https://elib.dlr.de/77646/
Document Type:Article
Title:Energy distribution and quantum yield for photoemission from air-contaminated gold surfaces under ultraviolet illumination close to the threshold
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Hechenblaikner, GeraldEADS Astrium, FriedrichshafenUNSPECIFIED
Ziegler, TobiasAstrium, FriedrichshafenUNSPECIFIED
Biswas, IndroDLRUNSPECIFIED
Seibel, ChristophUniversität Würzburg, Experimentelle Physik und Röntgen Research Center for Complex Material Systems (RCCM), WürzburgUNSPECIFIED
Schulze, MathiasDLRUNSPECIFIED
Brandt, NicoEADS Astrium, Astrium, FriedrichshafenUNSPECIFIED
Schöll, AchimAstrium, FriedrichshafenUNSPECIFIED
Bergner, PatrickUniversität Würzburg, Experimentelle Physik und Röntgen Research Center for Complex Material Systems (RCCM), WürzburgUNSPECIFIED
Reinert, Friedrich T.Universität Würzburg, Experimentelle Physik und Röntgen Research Center for Complex Material Systems (RCCM), WürzburgUNSPECIFIED
Date:29 June 2012
Journal or Publication Title:Journal of Applied Physics
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:111
DOI :10.1063/1.4730638
Page Range:p. 124914
Publisher:American Institute of Physics (AIP)
ISSN:0021-8979
Status:Published
Keywords:annealing, contact potential, electron spin polarisation, emissivity, gold, photoemission, sputtering, surface cleaning, surface contamination, total energy, ultraviolet photoelectron spectra
HGF - Research field:Energy
HGF - Program:Efficient Energy Conversion and Use (old)
HGF - Program Themes:Fuel Cells (old)
DLR - Research area:Energy
DLR - Program:E EV - Energy process technology
DLR - Research theme (Project):E - Elektrochemische Prozesse (old)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Electrochemical Energy Technology
Deposited By: Biswas, Indro
Deposited On:26 Nov 2012 11:23
Last Modified:08 Mar 2018 18:41

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