Studies on a-Se/n-Si and a-Te/n-Si Heterojunctions

Heterojunctions are fabricated by depositing amorphous selenium (a-Se) and amorphous tellurium (a-Te) films on n-type single (n-Si) wafers by the method of vacuum evaporation. The silicon wafers have surface orientation of (111). Resistivity of each silicon wafer is 5Ω-cm and carrier concentration of 8.30 x 10^14cm^-3. Two of the junction devices are annealed in a vacuum for half an hour. Current-voltage measurements are made at room temperature (298K). Rectification properties are observed in all the junctions. Barrier heights of a-Se/n-Si junctions are higher than a-Te/n-Si junctions. The current density in annealed junctions is lower than in as-deposited (unannealed) counterpart.