Effect of Structure Modifying Agents on the Structural, Morphological and Optical Features of Hydrothermally Grown ZnO

Morphology of Zinc Oxide (ZnO) is an important parameter to enhance the efficiency of optoelectronic devices. Morphology also plays a significant role in gas sensing properties of ZnO. In this research work, different morphologies of Zinc Oxide including nanorods, disks and flakes were obtained using Zinc Acetate, Sodium Dodecyl Sulphate and Trisodium Citrate as additives to a parent solution of Zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O) and Hexamethylenetetramine (HMTA, (CH₂)₆N₄) for hydrothermal growth. Use of Zinc Acetate as an additive has been rarely reported. This work presents the ability of Zinc Acetate to transform the morphology of ZnO nanorods to nanoneedles. Furthermore, in this study addition of Sodium Dodecyl Sulphate and Trisodium Citrate to the parent solution has shown potential for growing continuous granular films by the low cost and low temperature hydrothermal technique. Variation in crystallite size and band gap values with increasing concentration of Zinc Acetate, Sodium Dodecyl Sulphate and Trisodium Sulphate has been studied. Films with crystallite sizes of 7.48 nm and 6.77 nm were achieved with 5 mM Sodium Dodecyl Sulphate and 5 mM Trisodium Citrate respectively. The band gap of films produced with 5 mM Sodium Dodecyl Sulphate and with 5 mM Trisodium Citrate were 3.43 eV and 3.45 eV respectively. Therefore hydrothermal growth with Sodium Dodecyl Sulphate or Trisodium Citrate is a potential technique for obtaining granular ZnO films.