Photoconductivity of carbon aerogels

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Journal of Materials Research; (United States)

DOI:https://doi.org/10.1557/JMR.1993.0811· OSTI ID:6675025

Hosoya, M; Reynolds, G; Dresselhaus, M S ^[1]; Pekala, P W ^[2]

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1. Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2. Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

Photoconductivity was measured on a series of carbon aerogels to investigate their electronic properties. Carbon aerogels are a special class of low-density microcellular foams, consisting of interconnected carbon particles ([similar to]120 A diameter) and narrow graphitic ribbons ([similar to]25 A width) intertwined within each particle. Both the dark- and photo-conductivities show drastic changes in the temperature range 5--300 K, which are similar to those in [ital a]-Si and chalcogenide photoconductors. At high temperatures, the photoconductivity is dominated by the carrier recombination within each particle. The photoconductivity at low temperatures is dominated by the same carrier transport mechanism as that for the dark conductivity, which is based on hopping and tunneling transport. The activation energy values for transport and recombination identify the electronic structure of the particles among samples of different bulk density. The long decay time of the photoconductivity suggests a relaxation mechanism associated with the dangling bonds.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6675025
• Journal Information: Journal of Materials Research; (United States), Journal Name: Journal of Materials Research; (United States) Vol. 8:4; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
CARBON
COLLOIDS
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
ELEMENTS
GELS
NONMETALS
PHOTOCONDUCTIVITY
PHYSICAL PROPERTIES
RECOMBINATION
TEMPERATURE RANGE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K