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Title: Photoconductivity of activated carbon fibers

Abstract

The photoconductivity is measured on a high-surface-area disordered carbon material, namely activated carbon fibers, to investigate their electronic properties. Measurements of decay time, recombination kinetics and temperature dependence of the photoconductivity generally reflect the electronic properties of a material. The material studied in this paper is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000--2000m{sup 2}/g. Our preliminary thermopower measurements suggest that this carbon material is a p-type semiconductor with an amorphous-like microstructure. The intrinsic electrical conductivity, on the order of 20S/cm at room temperature, increases with increasing temperature in the range 30--290K. In contrast with the intrinsic conductivity, the photoconductivity in vacuum decreases with increasing temperature. The recombination kinetics changes from a monomolecular process at room temperature to a biomolecular process at low temperatures. The observed decay time of the photoconductivity is {approx equal}0.3sec. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The intrinsic carrier density and the activation energy for conduction are estimated to be {approx equal}10{sup 21}/cm{sup 3} and {approx equal}20meV, respectively. The majority of the induced photocarriers and of the intrinsic carriers are trapped, resulting inmore » the long decay time of the photoconductivity and the positive temperature dependence of the conductivity. 54 refs., 11 figs., 3 tabs.« less

Authors:
;  [1]
  1. (Massachusetts Inst. of Tech., Cambridge, MA (USA))
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (USA)
Sponsoring Org.:
DOE/DP
OSTI Identifier:
6824682
Alternate Identifier(s):
OSTI ID: 6824682; Legacy ID: DE91000814
Report Number(s):
UCRL-CR-104934
ON: DE91000814
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ACTIVATED CARBON; PHOTOCONDUCTIVITY; CARBON FIBERS; ELECTRICAL PROPERTIES; PHENOLS; TEMPERATURE DEPENDENCE; ADSORBENTS; AROMATICS; CARBON; ELECTRIC CONDUCTIVITY; ELEMENTS; FIBERS; HYDROXY COMPOUNDS; NONMETALS; ORGANIC COMPOUNDS; PHYSICAL PROPERTIES 360603* -- Materials-- Properties

Citation Formats

Kuriyama, K., and Dresselhaus, M.S. Photoconductivity of activated carbon fibers. United States: N. p., 1990. Web. doi:10.2172/6824682.
Kuriyama, K., & Dresselhaus, M.S. Photoconductivity of activated carbon fibers. United States. doi:10.2172/6824682.
Kuriyama, K., and Dresselhaus, M.S. Wed . "Photoconductivity of activated carbon fibers". United States. doi:10.2172/6824682. https://www.osti.gov/servlets/purl/6824682.
@article{osti_6824682,
title = {Photoconductivity of activated carbon fibers},
author = {Kuriyama, K. and Dresselhaus, M.S.},
abstractNote = {The photoconductivity is measured on a high-surface-area disordered carbon material, namely activated carbon fibers, to investigate their electronic properties. Measurements of decay time, recombination kinetics and temperature dependence of the photoconductivity generally reflect the electronic properties of a material. The material studied in this paper is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000--2000m{sup 2}/g. Our preliminary thermopower measurements suggest that this carbon material is a p-type semiconductor with an amorphous-like microstructure. The intrinsic electrical conductivity, on the order of 20S/cm at room temperature, increases with increasing temperature in the range 30--290K. In contrast with the intrinsic conductivity, the photoconductivity in vacuum decreases with increasing temperature. The recombination kinetics changes from a monomolecular process at room temperature to a biomolecular process at low temperatures. The observed decay time of the photoconductivity is {approx equal}0.3sec. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The intrinsic carrier density and the activation energy for conduction are estimated to be {approx equal}10{sup 21}/cm{sup 3} and {approx equal}20meV, respectively. The majority of the induced photocarriers and of the intrinsic carriers are trapped, resulting in the long decay time of the photoconductivity and the positive temperature dependence of the conductivity. 54 refs., 11 figs., 3 tabs.},
doi = {10.2172/6824682},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Aug 01 00:00:00 EDT 1990},
month = {Wed Aug 01 00:00:00 EDT 1990}
}

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