Scintillating zinc oxide ensconced in a carbon nanotube forest engineered by laser micro-welding

Abstract Herein, we report defect-introduction via focused-laser-beam (FLB) modification to introduce carbon defects into zinc oxide (ZnO) thin film. The approach begins with a carbon nanotube (CNT) array covered by a thin layer of sputtered Zn on top of the array. When FLB irradiates the covered CNT array under ambient conditions, effective laser energy absorption by CNT results in ZnOCNT nanohybrid formation, it also enables site-selective transformation to be achieved. By adjusting the laser power, the degree of carbon incorporation into the pristine Zn system can be tuned and this exerts some degree of control over the fluorescent properties of the nanohybrid. Generating a higher defect density increases the intensity and changes the wavelength of the fluorescence emitted by ZnO under ultraviolet (UV) excitation and enhances its field emission properties. In particular, the turn-on electric field (ETO) of the nanohybrid decreases. A lower ETO reduces the probability of arc formation, a significant problem currently undermining the industrial feasibility of field emission displays (FED). Electron emission from these samples can be enhanced by exciting the laser-treated sample with an external laser source. The normalised current produced increases by as much as 6µA/(mW/mm2) when the sample is excited by a 405 nm monochromatic laser.