Ultra-violet sensing characteristic and field emission properties of vertically aligned aluminum doped zinc oxide nanorod arrays

Vertically aligned Zinc oxide (ZnO) nanostructures become very important and useful materials in nanodevices fabrications due to its outstanding characteristics such as high aspect ratio, high electron mobility and large surface area availability.Vertically aligned ZnO nanorod array emerges as promising functional material which suitable for various application including dye-sensitized solar cell, light emitting diode, sensors and field emission displays. This paper introduces the prepartion of aligned ZnO nanorod arrays by a novel technique of sonicated sol-gel immersion. Ultra-violet (UV) sensing behavior and field emission characteristic have been investigated on vertically aligned aluminum (Al) doped zinc oxide (ZnO) nanorod arrays. Uniform and high coverage density of ZnO nanorod arrays have been successfully deposited on seeded-catalyst coated substrates. The synthesized nanorods have diameter sizes between 50 nm to 150 nm. The XRD spectra show Al doped ZnO nanorod array has high crystallinity properties with the dominancy of crystal growth along (002) plane or c-axis. UV photoresponse measurement indicates that Al doped ZnO nanorod array sensitively detects UV light with a large conductance increment after UV illumination exposure. The nanorod array shows good field emission properties with low turn on field and threshold field at 2.1 V/μm and 5.6 V/μm, respectively.