Electrical properties of ITO/benzylated cyclodextrins (β-CDs (Bz))/Al diode structures

Investigations of the electrical characteristics of benzylated cyclodextrins (beta-CDs (Bz)) diodes are reported. We present current voltage characteristics and impedance spectroscopy measurements performed on partially benzylated cyclodextrins beta-CDs (Bz) thin films in sandwich structures ITO/beta-CDs (Bz)/Al. The static electrical characterizations show a space charge limited conduction (SCLC) and a conductivity with power low frequency behavior characteristic of a hopping transport in disordered materials. The impedance spectra can be discussed in terms of an equivalent circuit model designed as a parallel resistor R-P and capacitor C-P network in series with resistor R-S. We extract numerical values of these parameters by fitting experimental data. Their evolution with bias voltages has shown that the SCLC mechanism is characterized by an exponential trap distribution. We estimated from the capacitance voltage characteristic an acceptor concentration of about 10(11) cm(-3) due to trap states. (c) 2006 NIMS and Elsevier Ltd. All rights reserved.