DataVXACS Energy LettersPaper
journal article·2019-10-11Open access

Surface Photovoltage-Induced Ultralow Work Function Material for Thermionic Energy Converters

Peter Schindler, Daniel C. Riley, Igor Bargatin, Kunal Sahasrabuddhe, Jared W. Schwede, Steven Sun, Piero Pianetta, Zhi-Xun Shen, Roger T. Howe, Nicholas A. Melosh

ACS Energy Letters· Volume 4· Issue 10
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Source abstract

Abstract

Low work function materials are essential for efficient thermionic energy converters (TECs), electronics, and electron emission devices. Much effort has been put into finding thermally stable material combinations that exhibit low work functions. Submonolayer coatings of alkali metals have proven to significantly reduce the work function; however, a work function less than 1 eV has not been reached. We report a record-low work function of 0.70 eV by inducing a surface photovoltage (SPV) in an n-type semiconductor with an alkali metal coating. Ultraviolet photoelectron spectroscopy indicates a work function of 1.06 eV for cesium/oxygen-activated GaAs consistent with density functional theory model predictions. By illuminating with a 532 nm laser we induce an additional shift down to 0.70 eV due to the SPV. Further, we apply the SPV to the collector of an experimental TEC and demonstrate an I-V curve shift consistent with the collector work function reduction. This method opens an avenue toward efficient TECs and next-generation electron emission devices.
Source: europepmc · Quality: candidate unverified · Source record ↗

Research context

Electronic materials

OpenAlex topics: Thermal Radiation and Cooling Technologies · Advanced Thermoelectric Materials and Devices · Advanced Thermodynamics and Statistical Mechanics

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States

Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States

Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, United States

Department of Applied Physics, Stanford University, Stanford, California 94305, United States

Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States

Cyclotron Road, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States

Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6315, United States

Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States

Funding

Oak Ridge Institute for Science and Education · Gordon and Betty Moore Foundation · Basic Energy Sciences · Austrian Science Fund · Bosch Energy Research Network

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