20 mA bidirectional laser triggering in planar devices based on vanadium dioxide thin films using CO2 laser

By utilizing a CO2 laser centered at similar to 10.6 mu m as an optical stimulus, we demonstrated bidirectional laser triggering in a two-terminal planar device based on a highly resistive vanadium dioxide ( VO2) thin film. The break-over voltage of the VO2-based device was measured as large as similar to 294.8 V, which resulted from the high resistivity of insulating VO2 grains comprising the thin film and the large electrode separation of the device. The bidirectional current switching of up to 20 mA was achieved by harnessing the dramatic resistance variation of the device photo-thermally induced by the laser illumination. The transient responses of laser-triggered currents were also analyzed when laser pulses excited the device at a variety of pulse widths and repetition rates. In the transient responses, a maximum switching contrast between off- and on-state currents was measured as similar to 7067 with an off-state current of similar to 2.83 mu A, and rising and falling times were measured as similar to 30 and similar to 16 ms, respectively, for 100 ms laser pulses. (C)2015 Optical Society of America