Effect of Hydrothermal Solutions on Optical and Electrical Properties of ZnO Nanowires Grown on a ZnO:Al Seed Layer for Improved Mechanical Performance

Abstract

ZnO nanowire arrays were fabricated by hydrothermal growth on Al-doped ZnO (ZnO:Al) seed layers coated on soda-lime silicate glass by sol–gel coating. The properties of the ZnO:Al seed layer were evaluated to obtain ZnO nanowires with the optimal size and length and to realize suitable adhesion of the ZnO:Al grains to the substrate. The optimal mechanical performance (adhesion and abrasion resistance) of the ZnO:Al seed layer was obtained at Al 1 at.%. The seed layers annealed between 400 and 500 C exhibited enhanced ZnO nanowire growth. Increasing the annealing temperature within this range improved the electrical and optical properties of the nanowires. Additionally, two chemical compounds, zinc acetate (ZA) and zinc nitrate (ZN), were used to compare the effects of the solution type on the hydrothermal growth. The nanowires grown in the ZA solution were thicker and had higher electrical conductivity compared to the ZN solution. The gamma transmission technique was used to determine the agglomeration of ZnO:Al nanospheres and to examine the crystallite size and density of the ZnO:Al seed layers.