Schottky barrier lowering in Al/Si/Al back-to-back Schottky contacts by embedded gold nanoparticles

Modification of current density in back-to-back Schottky contacts without further heat treatment processes is possible by embedding nanoparticles (NPs) into metal contacts with different work functions. In this work n-type Silicon (n-Si) back-to-back aluminum (Al) Schottky contacts embedded with gold (Au) NPs were fabricated using spin-coating technique. The effect of embedded NPs on the electrical properties were subsequently studied by current-voltage parameter analyzer. Effect of the density of Au NPs on Schottky barrier lowering and current density enhancement of the contacts were also studied and the energy band bending mechanism of Al/Si contacts with and without the NPs effect was proposed and discussed. The electrical results showed that by increasing the density of Au NPs spin-coated on Si, the current density in both bias directions has increased by more than two orders of magnitude. The increase in current density was attributed to the effect of NPs in electric field enhancement which subsequently resulted in Schottky barrier thinning and facilitation of field emission conduction and hence current density elevation.