Current-voltage and capacitance-voltage characteristics of polypyrrole/p-InP structure

Aydoğan Ş., Sağlam M., TÜRÜT A.

VACUUM, vol.77, no.3, pp.269-274, 2005 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Volume: 77 Issue: 3
  • Publication Date: 2005
  • Doi Number: 10.1016/j.vacuum.2004.10.003
  • Title of Journal : VACUUM
  • Page Numbers: pp.269-274


The polypyrrole/p-InP structure has been made by the electrochemical polymerization of the organic polypyrrole onto the p-InP substrate. The current voltage (I-V) and capacitance-voltage (C-V) characteristics of diode have been determined at room temperature and different frequencies. At each frequency, the measured capacitance decreases with increasing frequency due to a continuous distribution of the interface states in the frequency range 50 kHz-1 MHz. From the I-V characteristics of the polypyrrole/p-InP structure, ideality factor and barrier height (BH) values of 1.68 and 0.59 eV, respectively, were obtained from a forward-bias I-V plot. The diode shows non-ideal I-V behavior with ideality greater than unity. This is attributed to the interfacial layer, the interface states and barrier inhomogeneity of the device. As expected, the C-V curves gave a BH value higher than those derived from I-V measurements. This discrepancy can be explained from the fact that due to the different nature of the C-V and I-V measurement techniques, BHs deduced from them are not always the same. (c) 2004 Elsevier Ltd. All rights reserved.