EDP Sciences Journals List
Home 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?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.