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Voltage and temperature effects on the carrier mobility of CuPc organic thin films

F. HIJAZI1,2, N. CHOUEIB1, H. GHAMLOUCHE1,* , M. YASSINEa1

Affiliation

  1. Department of Physics, Lebanese University, Beirut, Lebanon
  2. XLIM UMR 6172 – Université de Limoges/CNRS, Limoges Cedex, France

Abstract

Voltage and temperature dependence of the carrier mobility of CuPc organic semiconductor is presented using impedance spectroscopy measurements and current–voltage characteristics. Through current–voltage curve, four distinct regions are identified. At low bias voltage an ohmic region is observed (zone 1). By increasing the voltage, a space charge limited region appears due to the existence of trap states (zone 2). A further increase in the voltage leads to a traps filled limit region (zone 3). The last observed region is a trap-free square one, where the current rises linearly (zone 4). From current-voltage curve, VΩ is found (0.18V) and used to calculate the carriers’ concentration (2×1020 e∙m˗3). From impedance spectroscopy measurements, the dependence of the mobility on temperature permits the identification of two types of activation energies. Furthermore, the variation of the mobility as a function of the voltage doesn’t obey completely the Poole–Frenkel’s law, since a slight deviation from linearity above certain applied voltage is observed..

Keywords

Carrier mobility, CuPc, Organic thin films, Impedance spectroscopy, Current−voltage characteristics.

Submitted at: Jan. 18, 2019
Accepted at: Aug. 20, 2019

Citation

F. HIJAZI, N. CHOUEIB, H. GHAMLOUCHE, M. YASSINEa, Voltage and temperature effects on the carrier mobility of CuPc organic thin films, Journal of Optoelectronics and Advanced Materials Vol. 21, Iss. 7-8, pp. 505-510 (2019)