Si nanowire semisphere-like ensembles as field emitters

Silicon nanowires assembled in micro- sized semispheres were synthesized through simple thermal evaporation without using any templates and metal particle catalysts; electron microscopy revealed that the nanowires within semisphere ensembles are well- aligned and evenly distributed; a typical nanowire array density was of similar to 4 x 10(9) cm(-2); field- emitting characteristics of the arrays were analyzed.