Effect of temperature and inhomogeneity on the yield of PtSi-n-Si photodetectors

The temperature dependence of the current-voltage characteristics of a PtSi/Si Schottky detector is investigated between 20 and 300 K, a temperature range that is much wider than what is usually reported in literature. The data is satisfactorily interpreted on the basis of a thermionic emission mechanism across an inhomogeneous barrier. The Schottky barrier inhomogeneities are shown to obey a single Gaussian distribution with a mean barrier height of 0.76 eV and a standard deviation of 30 meV at zero bias. The calculated detector's efficiency, while taking the barrier distribution into account, shows an increase with decreasing temperature that can be considered overall as marginal but becomes much more significant below 60 K and at wavelengths near the cut-off edge.