Preparation of patterned boron nanowire films with different widths of unit-cell and their field emission properties

Large-area patterned films of boron nanowires (BNWs) are fabricated at various densities by chemical vapor deposition (CVD). Different widths of unit-cell of Mo masks are used as templates. The widths of unit-cell of Mo masks are 100 mu m, 150 mu m, and 200 mu m, respectively. The distance between unit cells is 50 mu m. The BNWs have an average diameter of about 20 nm and lengths of 10 mu m-20 mu m. High-resolution transmission electron microscopy analysis shows that each nanowire has a beta-tetragonal structure with good crystallization. Field emission measurements of the BNW films show that their turn-on electric fields decrease with width of unit-cell increasing.