15 mA Bidirectional Laser Triggering in Two-Terminal Microdevices Based on Vanadium Dioxide Thin Films

By using an infrared laser diode with an oscillating wavelength of 1550 nm, we demonstrated 15 mA bidirectional laser triggering with an amplitude switching ratio of ~78.9 in a two-terminal microdevice based on a vanadium dioxide (VO 2 ) thin film, which was DC-biased at 3.35 V. The VO 2 -based device has only one conducting layer, i.e., one VO 2 patch, which facilitates the use of the triggering laser with a reduced spot diameter. The reduced beam spot can increase the maximum on-state current at the same illumination power, resulting in the improvement of the amplitude switching ratio. A specific bias voltage range enabling the bidirectional laser triggering was experimentally determined from the current-voltage characteristics of the VO 2 -based device with an electrode separation of 10 m and a current channel width of 30 m, which was measured in a current-controlled mode. In a closed-loop circuit constructed by serially connecting a standard resistor, a DC voltage source, and the device, the transient responses of light-triggered currents were also observed for response time analysis.