Schottky-barrier diodes were fabricated by evaporation of gold layers onto p-polycrystalline silicon wafers.Comparing the surface morphology of the substrate with the electronic and optoelectronic behavior of the Schottky diode,we are able to identify the influence of the grain boundaries.The current -voltage characteristics at different temperatures, spectral response,and Fowler＇s plot of photoelectronic measurments were investigated.It is found that the Schottky barrier height, phi, for Au/polycrystalline Si (P - type) depends on the grain boundary density d(B),which is defined as the length of grain boundary on the surface per unit area (inversely proportional to the average grain size).