Low work function, stable thin films

Patent · Sat Jan 01 00:00:00 EST 2000

OSTI ID:873453

Dinh, Long N ^[1]; Balooch, Mehdi ^[2]; Schildbach, Marcus A ^[3]

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1. Concord, CA
2. Berkeley, CA
3. Livermore, CA

Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 6162707
• OSTI ID: 873453
• Country of Publication: United States
• Language: English

Related Subjects

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thermal
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alkali
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oxygen
environment
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cs
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ultraviolet
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chemical compositions
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alkali metal
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annealing temperature
x-ray photoelectron
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simultaneously laser
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