Influence of Grain size on the Electrical Properties of {rm Sb₂Te₃} Polycrystalline Films

Resistance of vacuum deposited ${\rm Sb_2Te_3}$ films of thickness between 100-500nm has been measured in vacuum. It is found that the resistance of the polycrystalline films strongly depends on the grain size and inter-granular voids. The charge carrier are shown to cross this high resistivity inter- granular void by ohmic conduction. The barrier height as well as temperature coefficient of resistance are also shown to depend on the grain size and inter- grain voids.