Giant conductance response to light pulses in metallic nanowires

Experiments are presented showing a giant conductance response when a nanometer size gold wire is illuminated by light pulses. The results are basically as follows: (i) after illumination the conductance increases by factors of up to a hundred depending on the initial current and in a reproducible way; (ii) the conductance increases during the illumination pulses and after that, when the light is off, relaxes in a time of milliseconds; and (iii) the conductance changes in quantum steps, i.e. changes from the initial conductance to the final one in steps. The explanation of this giant conductance response is made in terms of changes in the nanowire section which are mechanically driven by temperature when the pulse is on and off. These results lead to an opto-electronic transistor gated by a light pulse. (C) 1998 Elsevier Science B.V. All rights reserved.