Forward and reverse bias current–voltage (I–V) characteristics in the metal–ferroelectric–semiconductor (Au/SrTiO₃/n-Si) structures at room temperature

The main electrical parameters of fabricated Au/SrTiO₃/n-Si (MFS) structures have been investigated by using various methods. The values of ideality factor (n) and zero-bias barrier height (Φ_B0) are calculated from the forward bias current–voltage (I_F–V_F) data as 0.60, and 0.48 eV from thermionic theory (TE) and Cheung functions, respectively. The value of R_s is also obtained from the Norde function and Cheung functions as 87.83 and 137.57 Ω, respectively. The discrepancy between these results can be attributed to the calculated method and the measured voltage range. Besides, the energy density distribution profile of interface state (N_ss) was obtained from the (I_F–V_F) data by taking into account voltage dependent barrier height (BH), n and without R_s. On the other hand, the possible current conduction mechanism (CCM) are determined by utilizing the In(I_F) versus In(V_F) and In(I_R) versus V_R^1/2 plots. The double logarithmic I_F–V_F plot shows three linear regions which are corresponding to low, moderate and high bias voltages with different slopes (m) as 2.40, 1.96 and 1.27 respectively. While the first region space charge limited current (SCLC) is dominated, the other two regions ohmic behavior is dominated. The field-lowering coefficient (β) was also obtained from the slope of In(I_R)–V^1/2 plot as 4.40 \(\times\) 10⁻⁶ eV⁻¹ m^1/2 V^1/2. This value of β is close to theoretical value of Poole–Frenkel emission (PFE) rather than Schottky emission (SE) mechanism.