Received: August 17, 2007

In Final Form: December 5, 2007

Abstract:

We report current rectification in a junction between two different nanoparticles. A monolayer of p-type nanoparticles (PbSe or PbS) and a monolayer of n-type nanoparticles (CdSe or CdS) assembled in sequence form such a junction. Here the nanoparticles, which have been characterized following standard experimental methods, are suitably capped to facilitate electrostatic assembly. While keeping the sequence of capping materials the same, if the order of the monolayers is reversed, the direction of current rectification becomes opposite. Junctions between two p-type or two n-type nanoparticle monolayers, on the other hand, do not exhibit current rectification. The rectifying and inverse-rectifying characteristics from pn and np junctions, respectively, and nonrectifying pp and nn junctions rule out any role of interfaces in observing the rectification. The results presented in this article show that rectifying nanodiodes are achieved from a suitable assembly of two nanoparticles.

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