Temperature dependence of electrical characteristics and interface state densities of Au/n-type Si structures with SnS doped PVC interface

Abstract

In this study, the electrical properties of Au/(SnS doped PVC)/n–Si structures were investigated in detail using current/voltage (IV) data in wide temperature range (80–340 K by 20 K steps). Some of the basic electrical parameters such as ideality factor (n), saturation current (I 0), and barrier height (Φ bo ) were obtained. When these parameters were extracted using thermionic emission (TE) theory, it was found that the value of n decreases whereas Φ bo increases with increasing temperature. This result can be explained by the barrier height (BH) inhomogeneity. The observed two linear regions in the plots of Φ bo –n, Φ bo –(1/2kT)1 and (n −1–1)–(1/2kT) in temperature regions of 80–160 K and 80–340 K form an evidence to the presence of Double Gaussian distribution (DGD). Using the plot of Φ bo –(1/2kT), the values of mean BH () and standard deviation (σ S) were found as 0.486 eV and 66 mV for first region, and 0.984 eV and 139 mV for second region, respectively. Thus, the effective Richardson constant (A*) was obtained using the interception point of the modified Richardson plot for these regions as 7.013 × 10−6 A.K−2cm−2 and 88.12 A.K−2cm−2, respectively. It is clear that A* value for second region is closer to theoretical value (=112 A.K−2cm−2 for n–Si). Finally, the energy dependent profile of the surface-states (Nss) was extracted using Card-Rhoderick method and Nss was found to range from ∼1012 (at 80 K) to 1013 eV−1 cm−2 (at 340 K).