spacer
EDP Sciences Journals List
Home arrow Document
Subscriber Authentication Point
   
Issue Eur. Phys. J. Appl. Phys.
Volume 37, Number 1, January 2007
Page(s) 1 - 9
Section Semiconductors and Related Materials
DOI 10.1051/epjap:2006135
Published online 15 November 2006

Eur. Phys. J. Appl. Phys. 37, 1-9 (2007)
DOI: 10.1051/epjap:2006135

Structural and electrical properties of thermally evaporated cobalt phthalocyanine (CoPc) thin films

H.S. Soliman1, A.M.A. El-Barry2, N.M. Khosifan1 and M.M. El Nahass2

1  Physics department, faculty of girls, Jedda, Saudi Arabia Kingdom
2  Physics Department, Faculty of Education, Ain Shams University, Cairo, Egypt

amall56@yahoo.com

(Received: 31 May 2006 / Received in final form: 22 August 2006 / Accepted: 28 August 2006 / Published online: 15 November 2006 )

Abstract
Thin films of CoPc of various thickness have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperature range (298-423 K). An estimation of mean free path ($\ell_{0}$) of charge carriers in CoPc thin films and bulk resistivity, $\rho_{B}$ was attempted. Measurements of thermoelectric power confirm that CoPc thin films behave as p-type semiconductors. The ac conductivity ( $\sigma _{ac}$) has been investigated in the frequency range (102-106 Hz) and temperature range (298-407 K). $\sigma _{\rm ac}$ is found to be proportional to $\omega ^{s}$ where $s \approx 0.879$ which is frequency and temperature independence. The ac conductivity interpreted by the correlated barrier hopping (CBH) model with centers of intimate valence alternation pairs type with a maximum barrier height, $W_{M} \approx 1.594$ eV.

PACS
72.20.-i - Conductivity phenomena in semiconductors and insulators.
77.55.+f - Dielectric thin films.
73.61.-r - Electrical properties of specific thin films.

© EDP Sciences 2006


What is OpenURL?