In-doped ZnO nanorods (NRs) were synthesized by hydrothermal method. The X-ray diffraction (XRD) patterns showed that the ZnO lattices expanded upon In doping. According to the scanning electron microscopy (SEM) images, the aspect ratio (length-to-width ratio) of the ZnO NRs decreased as the concentration of In(III) in the precursor solution increased from 0%to 1.0%(atomic fraction, x), and increased with further increases in the In(III) concentration from 1.0%to 5.0%. The nonlinear modulation of the aspect ratio of ZnO NRs is believed to be due to the competition between the subst itutional doping of In3+(InZn) and formation of InOOH intermediate, both of which are closely related to the behavior of In(OH)4-. In(OH)4-can be adsorbed onto zinc polar plane, and thus inhibits adsorption of Zn(OH)42-growth units. Furthermore, In(OH)4-can convert into InOOH, which can act as a crystal binder and enhance growth along the (002) plane. InZn can disrupt the zinc polar plane, resulting in the suppression of growth along the (002) facet. Therefore, the aspect ratio of ZnO NRs can be control ably modulated by changing the In concentration in the precursor solution. The current study furthers our understanding of the growth mechanism of In-doped ZnO, and presents a feasible method to prepare doped-ZnO NRs for real applications.%利用水热法合成了铟掺杂的氧化锌(In-ZnO)纳米棒. X射线衍射(XRD)结果表明铟掺杂能导致氧化锌晶格膨胀.扫描电镜(SEM)结果显示,随着前驱液中铟浓度的增加,氧化锌纳米棒的长径比先减小后增大,在铟原子浓度为1.0%(原子分数, x),长径比达到最小值；随着前驱液中铟浓度继续增加,长径比增大.从晶体生长角度考虑,溶液中存在四羟基铟(In(OH)4-)生长基元,该生长基元可转化为铟替位掺杂(InZn)和羟基铟氧化物(InOOH)两种状态,二者之间存在竞争关系,共同引起长径比的非线性变化.当铟原子分数小于1.0%时, InZn是主要存在形式,其能破坏锌极性面,从而抑制(002)晶面的生长.当铟原子浓度高于1.0%时,生成微量的InOOH,其能起到晶粒粘结剂的作用,促进(002)面的生长.因此,可以通过改变前驱液中铟的浓度,调控氧化锌纳米棒的长径比.本文阐述了In-ZnO的生长机理,并提供一种制备实用的掺杂氧化锌纳米棒的方法.
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