Scientists develop nanoscale ‘Etch-a-Sketch’ light sensor

Monday, November 15, 2010

LONDON - Researchers at the University of Pittsburgh have created a nanoscale light sensor that can be combined with near-atomic-size electronic circuitry to produce hybrid optic and electronic devices with new functionality.

The group, led by Jeremy Levy, of the Pitt’s School of Arts and Sciences, fashioned a photonic device less than 4 nanometers wide, enabling on-demand photonic interaction with objects as small as single molecules or quantum dots, reports Nature.

In another first, the tiny device can be electrically tuned to change its sensitivity to different colours in the visible spectrum, which may forgo the need for the separate light filters other sensors typically require.

The researchers produced the photonic devices via a rewritable nanoelectronics platform that works like a microscopic Etch A SketchTM, the drawing toy that initially inspired him.

His technique, first reported in 2008, is a method to switch an oxide crystal between insulating and conducting states.

Applying a positive voltage to the sharp conducting probe of an atomic force microscope creates conducting wires only a few nanometers wide at the interface of two insulators-a 1.2 nanometer-thick layer of lanthanum aluminate grown on a strontium titanate substrate.

The conducting nanowires can then be erased with reverse voltage, rendering the interface an insulator once more.

Levy and his colleagues demonstrated a robust method for incorporating light sensitivity into these electronic circuits, using the same techniques and materials. (ANI)

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