Doping rate, Interface states and Polarization Effects on Dielectric Properties, Electric Modulus, and AC Conductivity in PCBM/NiO:ZnO/p-Si Structures in Wide Frequency Range

Abstract

In order to study, in detail, the relationship of effect of NiO doping in ZnO on AC electrical-conductivity (sigma(ac)), complex-permittivity (epsilon*), complex-electric modulus (M*) and interface-states (N-ss), we have been used capacitance/conductance-voltage (C/G-V) measurements of the performed Al/PCBM/NiO:ZnO/p-Si structures over wide-range of frequency and voltage. For this reason, various-ratio (2, 10, and 20%) NiO doped ZnO layer were coated on the Si(p-type) wafer as an interlayer. The values of complex dielectric-constant/loss (epsilon'/epsilon), loss tangent (tan delta), ac electrical-conductivity (sigma(ac)), real/imaginary-components of complex electric modulus (M', M) were calculated from the C/G-V measurements as function of frequency between 0.5-2.5V by 100 mV steps. All parameters were found distinctly-function of frequency/voltage owing to the existence of N-ss, surface/dipole-polarizations and interlayer particularly at low and intermediate frequencies. The observed the higher value of dielectric constant (=2.5 for 2%(NiO) and 4.25 for 10 % (NiO)) even at 10 kHz show that (PCBM/NiO:ZnO) thin film can be successfully used instead of conventional low-dielectric SiO2. The value of sigma(ac) increase with increasing doping rate of NiO. Thus, the used high-dielectric organic thin film between metal and semiconductor can be also an advantageous for applications in place of conventional metal/oxide/semiconductor (MOS) structures.