Gaussian distribution of inhomogeneous barrier height in nanocrystalline graphite (NCG)/p-Si Schottky diodes

Abstract

Schottky characteristics of nanocrystalline graphite/p-Si junction were investigated using current-voltage measurements at various temperatures between 298 and 473 K. Using the thermionic emission theory, the extracted ideality factor reduces by 77% while Schottky barrier height increases by 46% with increasing temperature. The initial obtained value of Richardson constant, A∗ from this device was 7.92 × 10-10 Acm-2 K-2. This value is far smaller than the theoretical value of 32A cm-2 K-2 for p-Si which indicates inhomogeneity of a barrier height at the device interface. The Gaussian distribution plot was employed to explain the barrier height inhomogeneity, which gives the mean barrier height and standard deviation of 1.23 eV and 0.19 eV, respectively. By including the Gaussian distribution, the analysis of a modified Richardson plot gives a mean barrier height of 1.25 eV and a Richardson constant of 31.09 A cm-2 K-2, which are close to the theoretical values.