Synthetic Metals 162 (2012) 477–482 Contents lists available at SciVerse ScienceDirect Synthetic Metals journa l h o me page: www.elsevier.com/locate/synmet Dielectric, conduction and interface properties of Au/Pc/p-Si Schottky barrier diode Ahmet Altındal a,∗ , Mustafa Cos ¸ kun b , Özer Bekaro˘ glu c a Department of Physics, Yıldız Technical University, Davutpas ¸ a, Istanbul, Turkey b Department of Physics, Istanbul Medeniyet University, Göztepe, Istanbul, Turkey c Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey a r t i c l e i n f o Article history: Received 1 July 2011 Received in revised form 15 December 2011 Accepted 6 January 2012 Available online 14 February 2012 Keywords: Clamshel Dielectric MIS structure Interface trap Tunneling a b s t r a c t The dielectric properties and the ability of binuclear zinc(II) phthalocyanine of clamshell type compound in passivating silicon (Si) surfaces is studied by fabricating metal–insulator–semiconductor (MIS) capac- itors. The frequency and temperature dependence of the dielectric constant were discussed in the light of Koops model and hopping conduction mechanism. A detailed study of the effect of temperature on the ac conductivity of MIS structure at the temperatures between 300 K and 460 K was carried out. Based on the existing theories of ac conduction, it has been concluded that for low frequency region the dominant conduction mechanism in the sample is quantum mechanical tunneling at all temperatures, whereas for intermediate frequency region multihopping process is the dominant conduction mechanism. At higher frequencies, the behavior and the values of index s reveal a free band conduction mechanism. Interface properties of the fabricated MIS structure were investigated by means of conductance–voltage (G M –V G ) and the combination of low frequency and high frequency capacitance–voltage (C M –V G ) measurements at various fixed frequencies. The values of D it obtained from conductance and high–low frequency capac- itance measurements are 4.25 × 10 11 eV -1 cm -2 and 4.90 × 10 11 eV -1 cm -2 , respectively. This indicates the consistency of both the methods. The observed peaks in the G M –V G characteristics indicated that the losses are predominantly due to interface states. © 2012 Elsevier B.V. All rights reserved. 1. Introduction In the fields of electronics and optoelectronics, organic semi- conducting materials are very promising candidates for future technology of thin layers. Among them, phthalocyanines (Pcs) and its derivatives have attracted much attention in the past decades and found applications in novel electronic and photonic devices, such as junction diodes [1], organic light emitting diodes (OLEDs) [2,3], optical power limiting [4], photovoltaic, solar and fuel cells [5,6] and gas-sensing devices [7–9]. One of the most interesting features of the Pc molecules is that their physical and chemical properties such as, the band gap, valence and conduction band energies, charge transport mechanism, as well as the solubility can be freely altered via incorporation of different metal atoms at the center of the phthalocyanine ring or by changing the nature of the substituents on the periphery of the macrocyclic ring [10]. However the incorporation of organic molecules in the electronic devices shows still serious stability and processability limitations. At this stage one of the main needs is to find new stable organic ∗ Corresponding author. E-mail address: altindal@yildiz.edu.tr (A. Altındal). semiconducting materials [11]. It is well understood that stable, low leakage and high permittivity dielectric thin films are required for fabrication of novel microelectronics devices. Recently, we have synthesized many kinds of phthalocyanine derivatives for devel- oping new electronic, optoelectronic and gas sensing devices using their unique functions [12–14]. In the present work, we focused on studying the potential- ity of the Pc film for use in Au/insulator/p-Si Schottky barrier diode as insulator layer. For this purpose, a novel binuclear zinc(II) phthalocyanine of the clamshell type has been synthesized. Thus, a Schottky barrier diode using this phthalocyanine compound has been fabricated. The charge transport mechanism and dielec- tric parameters determined from capacitance–voltage (C M –V G ), conductance–voltage (G M –V G ) and frequency–impedance (f–Z) measurements for Au/Pc/p-Si MIS capacitors in the frequency range between 20 Hz and 2 × 10 6 Hz at different temperatures. 2. Experimental details The substrates used to prepare the MIS structure were p type (1 0 0) oriented silicon wafers with resistivity in the 8–10  cm range. The wafer was chemically cleaned using the RCA cleaning procedure (i.e. a 10 min boil in NH 4 + H 2 O 2 + 6H 2 O followed by a 0379-6779/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.synthmet.2012.01.002