The Investigation of Frequency and Voltage Dependence of Electrical Characteristics in Al/P3HT/p-Si (MPS) Structures

Abstract

Abstract Metal-polymer-semiconductor (Al/P3HT/p-Si) structures have been fabricated and their electrical characteristics have been investigated using capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements. These measurements were performed in the frequency and voltage range of 3 kHz-1MHz and ±5 V, respectively, at room temperature. The values of diffusion potential (VD), doping concentration of acceptor atoms (NA), Fermi energy level (EF) and barrier height (ФB) were obtained from the reverse bias C−2 vs V plot for each frequency by considering interface states (Nss), series resistance (Rs), and interfacial layer effects. All these parameters were found as strong functions of frequency and voltage. The values of both Nss and Rs decrease with increasing frequency. On the other hand, the value of Nss is prominent in the inversion and depletion regions at low frequency, but Rs and interfacial layer are prominent in the accumulation region at high frequency. Therefore, to see the effect of Rs both the C-V and G/ω-V plots were corrected for high frequencies. The voltage dependent profile of Nss and Rs were also obtained from Hill-Coleman and Nicollian-Brews method, respectively. Obtained results confirm that the values of Nss, Rs and interfacial layer are more effective on the impedance measurements