Abstract

Herein the growth mechanism of an un-doped zinc oxide (i-ZnO) and an Al-doped zinc oxide (AZO) was investigated using electrochemical techniques. Zinc and aluminum nitrates precursors were used in an aqueous bath solution, under a fixed potential of about –1.0 V, at 80°C. The variations of the morphological, structural, and optical properties of AZO were investigated in terms of Al³⁺ concentrations ranging from 0 to 4 atomic percentage in the starting solution. The X-ray diffraction patterns showed the hexagonal wurtzite structure for all samples. The effect of the lateral growth mechanism of AZO instead of the longitudinal growth process of ZnO was confirmed by calculating the texture coefficient and by studying the surface morphology under high magnification via scanning electron microscopy. It was found that the morphology evolved from hexagonal flat nanorods into a mixture of tapered hexagonal nanorods and nanosheets, to larger nanosheets by adding aluminum ions dopants. All films demonstrated a transmittance of about 80% in the visible range and exhibited a slight red shift in the absorption edge with Al³⁺ doping. The optical band gap of AZO nanosheets was found to be lower than that of i-ZnO nanorods. These findings provide fundamental understanding of the growth mechanism and shape control of a nanostructured zinc oxide.

中文翻译：

---

纳米ZnO的生长机理研究：光照对Al 3+掺杂的影响

摘要

在本文中，使用电化学技术研究了未掺杂的氧化锌（i-ZnO）和铝掺杂的氧化锌（AZO）的生长机理。锌和硝酸铝的前驱体在80°C的固定电位约–1.0 V的水溶液中使用。用Al ³⁺考察了AZO的形貌，结构和光学性质的变化。起始溶液中的浓度范围为0到4原子百分比。X射线衍射图显示所有样品的六方纤锌矿结构。通过计算织构系数并通过扫描电子显微镜在高放大倍数下研究表面形态，证实了AZO的横向生长机制而不是ZnO的纵向生长过程的作用。通过添加铝离子掺杂剂，发现形态从六角形扁平纳米棒演变成锥形六角形纳米棒和纳米片的混合物，再到较大的纳米片。所有薄膜在可见光范围内均显示出约80％的透射率，并且在吸收边缘处出现轻微的红移（Al ³⁺掺杂。发现AZO纳米片的光学带隙低于i-ZnO纳米棒的光学带隙。这些发现提供了对纳米结构氧化锌的生长机理和形状控制的基本理解。