P2–24: Controlled growth of ultra-long AlN nanowire arrays in different density and investigation of their emission behaviors

Controlled synthesis of ultra-long AlN nanowire arrays in different growth density has been successfully realized by direct nitridation of Al powders for the first time. These AlN nanowires have an average diameter of about 100 nm and their mean length is over 50 μm. All the synthesized ultra-long nanowires are pure single crystalline h-AlN structures with the growth orientation of [0001]. We propose the self-catalyzing vapor-liquid-solid (VLS) mechanism to illustrate their growth process. The field emission (FE) properties of three samples with different growth density of ultra-long AlN nanowire are compared, which shows that the sample with the most suitable growth density exhibits the best FE behaviors. Moreover, the FE performance of ultra-long AlN nanowire arrays is better than many nanostructures with excellent FE properties, which suggests that they should have a more promising future in vacuum electron devices if their emission uniformity can be effectively improved.