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

Abstract

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 –(1/2 kT ) 1 and ( n −1 –1)–(1/2 kT ) 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 –(1/2 kT ), the values of mean BH ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mi mathvariant="normal">Φ</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>b</mml:mi> <mml:mi>o</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) 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 −2 cm −2 and 88.12 A.K −2 cm −2 , respectively. It is clear that A* value for second region is closer to theoretical value (=112 A.K −2 cm −2 for n –Si). Finally, the energy dependent profile of the surface-states (N ss ) was extracted using Card-Rhoderick method and N ss was found to range from ∼10 12 (at 80 K) to 10 13 eV −1 cm −2 (at 340 K).

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