Frequency-dependent capacitance and conductance characteristics and current transport mechanisms of Schottky diodes with TPA-IFA organic interfacial layer

Abstract

In this study, a Schottky barrier diode with an Al/TPA-IFA/p-Si structure was fabricated using spin coating and thermal evaporation methods. Using forward and reverse bias I–V measurement, we examined the key electrical characteristics of the Al/TPA-IFA/p-Si diode, including Φ_b, n, R_s, and N_ss; we also estimated V_D, N_A, E_F, 〖∆Φ〗_b, W_D, Φ_b and N_ss using C–V measurements under the different frequencies (10, 50, 100, 500 kHz, and 1 MHz) at room temperature. Using I–V data and the Thermionic Emission (TE) theory, basic electrical parameters such as ideality factor (n), and barrier height (Φ_b) values were computed as 3.01 and 0.716 eV. The fundamental diode parameters are highly frequency-dependent. It was also found that the series Resistance (R_s) values reduced with increasing frequency, but the barrier height (Φ_b) and the width of the depletion layer (W_D) increased. It was found that when frequency increased, the diode capacitance reduced for our new Schottky-type diode. The diode's potential conduction mechanisms were examined through the utilization of reverse "ln" I-V^0.5 and forward "ln" I-V graphs. The transport properties of Al/TPA-IFA/p-Si diode are primarily governed by ohmic conduction, Space Charge Limited Current (SCLC), and Trap Charge Limited Current (TCLC) mechanisms at low, moderate, and high voltages, respectively. It was concluded that the Poole-Frenkel Emission (PFE) mechanism was dominant for the Al/TPA-IFA/p-Si diode. Ultimately, the findings confirmed that the TPA-IFA-based diode could be obtained for the electronic application.