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Proceedings Paper

Photoconductive response of type IIa diamond in the 222-353-nm range
Author(s): Mahadevan Krishnan; Evgenii E. I. Lipatov; D. Parks; Alexei N. Panchenko; Jochen Schein; Victor F. Tarasenko; J. Thompson
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Paper Abstract

Diamond radiation detectors (DRDs) operate on the principle of photoconductive response of the normally insulating, Type IIa diamond when dosed by electromagnetic radiation or high energy particles. As detectors, they offer fast response (~100 ps) and can handle high radiation doses (~1 GGy) without degradation. Diamond also offers significant advantages over semiconducting materials as a compact, bi-polar, high voltage switching medium because of its high dielectric strength and thermal conductivity. However, the wide band-gap of diamond and its normally insulating state impose stringent requirements on the trigger radiation that is used to make the diamond conductive. This paper describes a simple model for conduction in diamond, and compares this model with experimental conductivity as measured in a natural diamond Type IIa radiation detector that was irradiated by laser excitation at various wavelengths from 222-353 nm. The DRD geometry consisted of a 3x1x0.5 mm3 Type IIa diamond with metallization on the 3x0.5mm2 sides. The DRD was exposed to laser light in the orthogonal 3x1 mm2 plane. Agreement with the measured data is achieved by fitting a parameter (defined here as β) at the various irradiation wavelengths. This fitting parameter is itself a function of two physical quantities: α, the absorption coefficient of the diamond and εo, the ionization cost to produce a hole-pair. Using published values of α, we deduce values of εo and compare them with published values for Type IIa diamond in the deep UV to soft x-ray regions. This model also provides a basis for design of high voltage diamond switches that are triggered by near-bandgap (220-250 nm) UV radiation.

Paper Details

Date Published: 3 May 2004
PDF: 8 pages
Proc. SPIE 5483, Atomic and Molecular Pulsed Lasers V, (3 May 2004); doi: 10.1117/12.563010
Show Author Affiliations
Mahadevan Krishnan, Alameda Applied Sciences Corp. (United States)
Evgenii E. I. Lipatov, High Current Electronics Institute (Russia)
D. Parks, Alameda Applied Sciences Corp. (United States)
Alexei N. Panchenko, High Current Electronics Institute (Russia)
Jochen Schein, Alameda Applied Sciences Corp. (United States)
Victor F. Tarasenko, High Current Electronics Institute (Russia)
J. Thompson, Alameda Applied Sciences Corp. (United States)

Published in SPIE Proceedings Vol. 5483:
Atomic and Molecular Pulsed Lasers V
Victor F. Tarasenko, Editor(s)

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