Creating gradients of nanostructure on the surface has found broad applications such as enhanced optical spectroscopy, optical storage of information, and broadband solar energy harvesting. Here, a facile strategy is presented for fabricating gradient nanoparticle arrays with tunable size. It takes a ZnO:Ga microwire as the starting material, and the Ga³⁺ doping gradient along the microwire is induced by the high voltage applied. Such a doping gradient facilitates the formation of a temperature gradient in a Joule heating process. And this temperature gradient produced by this technique can be as high as 800 °C/mm, which could be later used for gradient annealing of thin metal films. After annealing, the thin metal films turn to gradient nanoparticle arrays. The obtained gradient nanoparticle arrays are confirmed effective in multi-wavelength surface enhanced Raman scattering enhancement.

在表面上创建纳米结构梯度已经发现了广泛的应用，例如增强的光谱学、信息的光学存储和宽带太阳能收集。在这里，提出了一种用于制造尺寸可调的梯度纳米颗粒阵列的简便策略。它以 ZnO:Ga 微线为起始材料，Ga ³⁺沿微线的掺杂梯度是由施加的高电压引起的。这种掺杂梯度有助于在焦耳加热过程中形成温度梯度。而这种技术产生的温度梯度可高达800℃/mm，以后可用于薄金属薄膜的梯度退火。退火后，金属薄膜变成梯度纳米颗粒阵列。所获得的梯度纳米颗粒阵列被证实在多波长表面增强拉曼散射增强中有效。