Manipulation and trapping of semiconducting ZnO nanoparticles into nanogap electrodes by dielectrophoresis technique

The assembly of ZnO nanoparticles into nanogap electrodes using ac dielectrophoresis (DEP) process is reported. DEP parameters such as frequency, voltage, and time were optimized to assemble minimum number of nanoparticles into nanogap electrodes. Frequency variation study revealed that positive DEP is active at frequencies less than 500 kHz; whereas negative DEP starts dominating at 1 MHz. The fabricated device exhibited a nonlinear I-V characteristic and under ultraviolet (UV) illumination a remarkable change in conductivity of one order of magnitude was observed. The results show the potential for realizing future optoelectronic devices such as miniaturized UV sensor.