Abstract
Thin films of 7,7',8,8' tertracyanoquinodimethane (TCNQ) were deposited using thermal evaporation technique. TCNQ was found to be polycrystalline in powder form and preferred to orient at one plane in thin films. The temperature dependence of the electrical resistivity of Au/TCNQ/Au device was studied. TCNQ thin films were deposited on p-GaAs single crystal substrate; the current-voltage and capacitance-voltage for TCNQ/p-GaAs junction sandwiched between two gold electrodes were investigated. The current of the device obeys the thermionic emission model in the voltage range of 0<V<0.5. The diode parameters such as rectification ratio, series resistance, quality factor and mean potential barrier height were evaluated. The space charge limited conduction dominated by single trapping level is applicable in the voltage range 0.5<V<1.5. The capacitance-voltage measurements showed that the formed junction is abrupt in its nature and the built-in potential is determined. Under illumination, the cell exhibited a photovoltaic characteristic from which the photovoltaic parameters such as open circuit voltage, short circuit current, fill factor and conversion efficiency were calculated. (C) 2011 Elsevier B.V. All rights reserved.