The possible current-conduction mechanism in the Au/(CoSO₄-PVP)/n-Si junctions

Abstract

The possible current-conduction mechanism (CCMs) of the Au/CoSO₄-PVP/n-Si junctions was investigated using temperature-dependence current–voltage (I–V) experiments over 100–360 K. The experimental results showed that the value of BH increases approximately linearly with increasing temperature. Such positive temperature coefficient (α = ΔΦ_B0/ΔT) is in agreement with the reported negative temperature coefficient of the bandgap of Si (= − 0.473 meV/K). The (n_ap⁻¹−1) vs q/2kT curves have different characters in two temperature ranges due to having separate two barrier distributions. The ρ₂ and ρ₃ values obtained from intercept and slope of these curves as 0.521 V and 0.011 V for 240–360 K temperature range and 0.737 V and 0.004 V for the 100–220 K range. This results show that the high temperature region with smaller ρ₂ and larger ρ₃ voltage deformation coefficients has a wider and greater of the barrier height distribution than the second region. As an evidence for the Gaussian distribution, the Φ_B0 and standard deviation (σ₀) were derived from the intercept and slope of the Φ_B0-q/2kT curves as 1.14 eV and 0.163 V at high temperatures and 0.62 eV and 0.088 V at low temperatures. The Richardson constant obtained as 102 A/cm²K² for 240–360 K temperature range using standard deviation value which is similar to the theoretical Richardson constant value of silicon (112 A/cm²K²). For each temperature, the profile of N_ss vs (E_c–E_ss) was provided using the voltage-dependent effective barrier height (Φ_e) value. It was observed that these surface conditions decreased with increasing temperature.