Observation of negative differential resistance and electrical bi-stability in chemically synthesized ZnO nanorods

Abstract

Zinc oxide nanorods/p-Si heterostructures have been fabricated by depositing the chemically synthesized ZnO nanorods on p-type silicon substrate. Heterostructure shows electrical bi-stability and negative differential resistance (NDR) only at the beginning of the forward bias region, and these phenomena have been explained with the help of energy band diagram. An explanation is proposed for the origin of electrical bi-stability in light of the electric field induced charge transfer across the junction, and the NDR phenomena could be attributed to interfacial traps and defect level that arises due to oxygen and zinc interstitial vacancies. Room temperature photoluminescence measurement of ZnO nanorods exhibits the emission peaks at about 466 nm and 566 nm which are attributed to oxygen vacancies and Zn interstitials. A correlation between NDR and blue emission phenomena in the ZnO nanorods due to defects states has been established.