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

Abstract 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.