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Proceedings Paper

Direct deposition of GaN-based photocathodes on microchannel plates
Author(s): Amir M. Dabiran; Andrew M. Wowchak; Peter P. Chow; Oswald H. W. Siegmund; Jeffrey S. Hull; James Malloy; Anton S. Tremsin
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Paper Abstract

Epitaxial growth of p-type GaN-based UV photocathode by RF plasma assisted molecular beam epitaxy (MBE) on sapphire, fused silica, and alumina substrates was investigated. The electrical measurements indicted the growth of highly p-type GaN films as thin as 0.1 μm on c-plane sapphire with a thin AlN nucleation layer. Polycrystalline p-type GaN was obtained for growth on fused silica and alumina. Negative electron affinity (NEA) photocathodes were fabricated by cesium activation of the p-type GaN films in vacuum. Quantum efficiency for UV detection on different substrates was then characterized. To study the integration of UV photocathodes with MCPs, direct deposition of p-type GaN films on glass MCPs were done at low growth temperatures by MBE. The detection efficiency of polycrystalline p- GaN photocathodes in reflection mode was much less than the high quality p-type GaN films on sapphire, however, it was comparable to the detection efficiency of the latter measured in the semitransparent mode. This indicates the potential for fabrication of improved photocathodes with higher gain and better spatial and temporal resolutions.

Paper Details

Date Published: 6 February 2009
PDF: 7 pages
Proc. SPIE 7212, Optical Components and Materials VI, 721213 (6 February 2009); doi: 10.1117/12.809503
Show Author Affiliations
Amir M. Dabiran, SVT Associates, Inc. (United States)
Andrew M. Wowchak, SVT Associates, Inc. (United States)
Peter P. Chow, SVT Associates, Inc. (United States)
Oswald H. W. Siegmund, Univ. of California, Berkeley (United States)
Jeffrey S. Hull, Univ. of California, Berkeley (United States)
James Malloy, Univ. of California, Berkeley (United States)
Anton S. Tremsin, Univ. of California, Berkeley (United States)

Published in SPIE Proceedings Vol. 7212:
Optical Components and Materials VI
Shibin Jiang; Michel J. F. Digonnet; John W. Glesener; J. Christopher Dries, Editor(s)

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