Metal–semiconductor junction in silicon nanostructures: role of interface traps

Silicon nanostructures have been prepared on Si wafer using electrochemical etching process. The transformation of aluminum/nanostructured Si junction from Schottky to Ohmic nature has been observed by varying the annealing temperature. This phenomenon has been explained by the temperature dependent shifting of energy levels of defects states instrumental in trapping charges within the forbidden band gap of Si nanostructures. The Aluminum (Al)/nano-Si junction shows asymmetric nature at room temperature and then changes to ohmic at moderate annealing temperature. Finally, at high temperature the junction becomes rectifying in nature. This transition has been explained on the basis of Fermi level pinning due to the modification of distribution of the non-stoichiometric silicon oxide related defect states present at the nanocrystalline Si core-oxide shell interface.