Dielectric properties, electrical modulus and current transport mechanismsof Au/ZnO/n-Si structures

Au/ZnO/n-Si (MIS) structures were fabricated by using the RF sputtering method and their complex dielectric constant (ε^*=ε’-jε’’), electric modulus (M^*=M′+ jM’’) and electrical conductivity (σ?=?σ_dc+σ_ac) values were investigated as a function of frequency (0.7?kHz-1?MHz) and voltage (?6 – (+6?V)) by capacitance-voltage (C-V) and conductance-voltage (G/ω-V) measurements to get more information on the conduction mechanisms and formation of barrier height between Au and n-Si. The lnσ-Lnf plots have two different regions corresponding to low-intermediate and high frequencies. Such behavior of lnσ?lnf plots shows that the existence of two different conduction mechanisms (CMs) at low-intermediate and high frequencies. Moreover, the reverse bias saturation current (I_o), ideality factor (n), barrier height (Φ_Bo) were determined from the forward bias I-V data and they were found as a strong function of temperature. The value of n especially at low temperature is considerably higher than unity. The values of $\stackrel{?}{\Phi }$_B0 and standard deviation(σ_s) were found from the intercept and slope of Φ_Bo-q/2kT plots as 0.551?eV and 0.075?V for the region I (80–220?K) and 1.126?eV and 0.053?V for the region II (220–400?K), respectively. The values of $\stackrel{?}{\Phi }$_Bo and effective Richardson constant (A^*) were found from slope and intercept of activation energy plots as 0.564?eV and 101.084?Acm^?2 K^?2 for the region I and 1.136?eV and 41.87?Acm^?2 K^?2 for the region II, respectively. These results confirm that the current-voltage-temperature (I-V-T) characteristics of the fabricated Au/ZnO/n-Si SBDs can satisfactorily be explained on the basis of TE theory with double GD of the BHs.