Pd Schottky Contacts on Sol–Gel Derived ZnO Thin Films With Nearly Ideal Richardson Constant

This letter reports the temperature-dependent analysis of measured I-V characteristics of Pd/ZnO thin filmbased Schottky diodes grown on n-Si (100) substrates by sol-gel method. Assuming a Gaussian distributed barrier height at the Pd/ZnO interface with a standard deviation (σ₀) around a mean barrier height qφ_B,m, the analysis estimates the value of Richardson constant ~31.67 Acm^-2K^-2, which is not only very close to its theoretical value of ~32 Acm^-2K^-2 (for m_e* = 0.27m₀), but also the best result reported so far for ZnO-based Schottky contacts. The estimated value of the zero-bias mean barrier height (~1.39 eV) at T = 0 K is also observed to be very close to its theoretical value of 1.42 eV (for work function of Pd = 5.12 eV and electron affinity of ZnO = 3.7 eV).