Capacitance studies of Ag / ClAlPc / ITO schottky device

Summary form only given. Organic photoconducting materials hold the promise of low cost solar calls because they have a variety of absorption in the visible region. A close examination of C-V measurement over a wide range of frequency is needed to characterise the metal organic semiconductor interface. This paper deals with the characterisation of Ag/ClAlPc/ITO device by capacitance measurements. The device Ag/C1AlPc/ITO was made by successive vacuum thermal evaporation of ClAlPc and Ag on chemically cleaned ITO substrate. All the evaporation were carried out during same pump down at a back ground pressure less than 1.5 x 10/sup -5/ Torr. The capacitance measurements were taken on HP-LCZ meter at different frequencies with different d.c. bias. In orkanic semiconducting materials the use of low frequencies is often necessary to allow the trapped charge to equilibrate with a.c. probing voltage. The device Ag/ClAlPc/ITO has been studied in frequency range from 100 hz to 100 khz. The conductance (G) varies more than two order of magnitude in low frequency range and at higher frequencies a plateau is obtained which correlates with the electrical properties of the bulk material which is the most conductive part of the CIAIPc layer. The capacitance are also strongly affected by the application of forward bias and not effect of reverse bias. These result indicate that the Ag-ClAlPc form a barrier and ITO-ClAlPc is ohmic contact. Various device parameters have been calculated from the capacitance - voltage measurements and are discussed in details.