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 are100 μm, 150 μm, and 200 μm, respectively. The distance between unit cells is 50 μm. The BNWs have an average diameter of about 20 nm and lengths of 10 μm–20 μm. High-resolution transmission electron microscopy analysis shows that each nanowire has a β-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.
For the first time we fabricated ZnO membranes with thicknesses of 2.4 nm by a facile one-pot synthesis in aqueous solution.The crystal analysis revealed that the hexagonal ZnO membranes were about 10 atomic layers in thickness.The ZnO membranes bent,scrolled,intersected with each other,and self-assembled to particles in micrometre size.The hierarchical assemblies showed sponge-like structures with room inside.In the growth process,a cationic polyelectrolyte was utilized to modulate growth behavior of the ZnO crystals.As a result,the preferred growth direction of ZnO membranes is along 0110,which was perpendicular to[0001]growth direction in a typical hydrothermal synthesis.The growth mechanism of the membranes was also discussed.
