The investigation of frequency dependent electric and dielectric properties of Au/P3HT:F4-TCNQ/n-Si Schottky barrier diode prepared by using polymer interface layer

In the last few decades, the polymeric organic materials have been a subject of intensive research. The main reasons of being the center of attention of organic polymers in semiconductor technology are including low-temperature processing, low cost, easy fabrication techniques and large area processing, allow the variety of large application fields and opportunity to produce of high performance devices. Through these properties, many devices can be manufactured with organics such as organic field effect transistors (OFETs), organic thin film transistors (OTFTs), Schottky diodes and organic light emitting diodes (OLEDs). Schottky barrier diodes (SBDs) are the most widely used diodes in electronic devices, because of their faster response time, switching ability under the high frequency signals and low forward voltage drop compared to other diodes. In this thesis, the dielectric properties of the gold/poly (3-hexylthiophene):2,3,5,6-tetrafluoro-7,7,8,8- tetracyanoquinodimethane/n-type silicon (Au/P3HT:F4-TCNQ/n-Si) metal-polymer-semiconductor (MPS) Schottky barrier diode (SBD) structure were investigated. Capacitance- voltage (C-V) and conductance-voltage (G/w-V) measurements were performed on -10 V – +10 V voltage range, in 10 kHz – 2 MHz frequency range, , at room temperature and in the dark. Resistance (Ri) and interface state density (Nss) parameters were obtained using the values of capacitance and conductivity. The intensity of the peaks in the resistance curves and the Nss values decrease by increasing the frequency. The frequency and voltage dependent dielectric constant (ε'), dielectric loss (ε''), ac conductivity (σac), loss tangent (tanδ) and the real and imaginary parts of electric modulus (M' and M'') were calculated by using C-V and G/w-V measurements. The experimental results show that ε', ε'', σac, M' and M'' parameters are robust functions of the frequency for the Au/P3HT:F4-TCNQ/n-Si SBDs. If ε' and ε'' parameters of the Au/P3HT:F4-TCNQ/n-Si SBDs decrease, σac, M' and M'' parameters increase with increasing the frequency for each voltage values. On the other hand, tanδ remain almost constant even though the frequency increases. Finally, it can be concluded that σac, ε', ε'', M' and M'' parameters are strongly dependent on the frequency for the Au/P3HT:F4-TCNQ/n-Si SBDs.