A comparative study on the electrical properties and conduction mechanisms of Au/n-Si Schottky diodes with/without an organic interlayer

In order to see an interlayer on the electrical parameters and conduction mechanisms (CMs), both the metal–semiconductor (MS) and Au/(MgO-PVP)/n-Si Schottky diodes (SDs) were grown onto the same wafer with   〈100〉 orientation and 350 μm thickness. Next, their electrical parameters, such as the ideality factor (n), barrier height (Φ_B), and series resistances (R_s) were obtained from the current–voltage (I–V) measurements using thermionic emissions, theory, and Cheung and Norde functions and compared. The energy-dependent distribution of interface traps/states (D_it/N_ss) of these two structures were extracted from the I–V data in the forward biases by considering the voltage-dependent n and Φ_B. Experimental results confirmed that the N_ss for a metal–polymer–semiconductor is considerably lower than for an MS, and it increases from the mid-gap towards the edge of the conduction band (E_c). The ln(I)–ln(V) curves have three straight lines which correspond to low, moderate, and high biases, and CM is governed by ohmic, trap/space-charge-limited current, respectively. When comparing these results, MgO-PVP leads to considerably improving the performance of the MS in respect of lower values of N_ss, R_s, the reverse saturation current (I_o) and higher values of the rectifying rate, Φ_B, and the shunt resistance (R_sh), and hence it can be successfully used instead of a traditional insulator interlayer.