Electrical properties of Au/polyvinylidene fluoride/n-InP Schottky diode with polymer interlayer

The effect of polyvinylidene fluoride (PVDF) polymer interlayer on the rectifying junction parameters of Au/n-InP Schottky diode has been investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. The calculated barrier heights (BHs) are 0.57 eV (I-V), 0.72 eV (C-V) and 0.73 eV (I-V), 0.88 eV (C-V) for the Au/n-InP and Au/PVDF/n-InP Schottky diodes, respectively. Results showed that the BH of the Au/PVDF/n-InP Schottky diode is higher than that of the Au/n-InP Schottky diode, and that the PVDF film increases the effective BH by influencing the space charge region of the n-type InP. The values of the barrier height, ideality factors and series resistance estimated by I-V, Cheung's and Norde methods are compared. Experimental results showed that the interface state density of the Au/PVDF/n-InP Schottky diode is lower than that of the Au/n-InP Schottky diode. Further, the reverse leakage current conduction mechanism is investigated. Schottky emission mechanism is found to dominate the reverse leakage current in the Au/n-InP Schottky diode. However, for the Au/PVDF/n-InP Schottky diode, the Schottky conduction mechanism is found to be dominant in the higher bias region, whereas the Poole-Frenkel conduction is found to be dominant in the lower bias region. Apart from that, the discrepancy between BHs determined from I-V and C-V techniques is explained. Besides, the capacitance-frequency (C-f) and conductance-frequency (G-f) characteristics of the Au/PVDF/n-InP Schottky diode are discussed.