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

Here we report the temperature dependent performance of Al/rGO-ZnCdS Schottky barrier diode(SBD) in the range of 303 K-453 K. 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 × 10−8 A/cm2 K2 and 1.4 × 10−7 A/cm2 K2 in the temperature range 303-363 K and 378-423 K respectively, which are much lower than the theoretical value of 32 A/cm2 K2. 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 1.47 eV and 1.26 eV and standard deviations(σs) of 0.22 V and 0.18 V. The modified activation energy plot of ln(I0/T2)-(q2σ2/2k2T2) yields ϕb0‾ and A∗ values as 1.49 and 1.26 eV, and 59.18 A/cm2 K2 and 32.29 A/cm2 K2, respectively. Particularly the A∗ value of 32.29 A/cm2 K2 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.