In a recent study published in the journal Nanotechnology, researchers at Korea University in Seoul, Korea, have investigated the use of n-type ZnO nanowires decorated with a discrete configuration of p-type Cr2O3 nanoparticles. The team has found that the combination is very promising for detecting trimethylamine (TMA) in a highly selective and sensitive manner.

TMA is secreted from the decay of dead fish and provides a good measure to evaluate their freshness. "The nanowire/nanoparticle sensor could be integrated in a mobile phone or other small portable electronic devices," explained Jong-Heun Lee, who leads the Functional nanostructured materials laboratory.

Enhanced response

The response to TMA of Cr2O3-decorated ZnO nanowires was 17.8, which was 3.3 times higher than prisitine ZnO nanowires. What's more, the selectivity toward TMA was significantly enhanced by the decoration of Cr2O3. This was explained by the catalytic effect of Cr2O3 towards TMA and the extension of the electron depletion layer via the formation of radial p-n junctions.

In further work, the scientists will examine the formation and configurational design of nanoscale p-n junctions using different oxide semiconductors for detecting specific gases. The group also plans to use similar nanoarchitectures to make new LED devices.

Full details are available in the journal Nanotechnology.