Temperature dependent properties of Al/rGO-ZnCdS Schottky diode and analysis of barrier inhomogeneities by double Gaussian distribution

Abstract

Here we report the temperature dependent performance of Al/rGO-ZnCdS Schottky barrier diode(SBD) in the range of 303K–453K. Ideality factor(n) and Series resistance(Rs) of the SBD decreased, while barrier height (BH)(ϕb0) increased with increasing temperature. Richardson constant (A∗) was obtained as 2×10−8A/cm2K2 and 1.4×10−7A/cm2K2 in the temperature range 303–363K and 378–423K respectively, which are much lower than the theoretical value of 32A/cm2K2. The strong temperature dependence of BH and the large discrepancy in A∗ has been precisely explained by assuming a Gaussian distribution (GD) of the BHs due to BH inhomogeneities at the metal-semiconductor interface. The results reveal the existence of a double GD with mean BH values (ϕb0‾) of 1.47eV and 1.26eV and standard deviations(σs) of 0.22V and 0.18V. The modified activation energy plot of ln(I0/T2)-(q2σ2/2k2T2) yields ϕb0‾ and A∗ values as 1.49 and 1.26eV, and 59.18A/cm2K2 and 32.29A/cm2K2, respectively. Particularly the A∗ value of 32.29A/cm2K2 is extremely close to the theoretical value. The analysis confirmed that temperature dependent I-V characteristics of our SBD can be successfully explained with a double GD of the BHs.