Grain coalescence has been applied in many areas of nanofabrication technology, including modification of thin-film properties, nanowelding, and self-assembly of nanostructures. However, very few systematic studies of self-assembly using the grain coalescence, especially for three-dimensional (3D) nanostructures, exist at present. Here, we investigate the mechanism of plasma triggered grain coalescence to achieve the precise control of nanoscale phase and morphology of the grain coalescence induced by exothermic energy. Exothermic energy is generated through etching a silicon substrate via application of plasma. By tuning the plasma power and the flow rates of reactive gases, different etching rates and profiles can be achieved, resulting in various morphologies of grain coalescence. Balancing the isotropic/anisotropic substrate etching profile and the etching rate makes it possible to simultaneously release 2D nanostructures from the substrate and induce enough surface tension force, generated by grain coalescence, to form 3D nanostructures. Diverse morphologies of 3D nanostructures have been obtained by the grain coalescence, and a strategy to achieve self-assembly, resulting in desired 3D nanostructures, has been proposed and demonstrated.

Open image in new window

晶粒聚结已应用于纳米加工技术的许多领域，包括薄膜特性的改性，纳米焊接和纳米结构的自组装。但是，目前很少有使用晶粒聚结的自组装的系统研究，特别是对于三维（3D）纳米结构。在这里，我们研究了等离子体触发晶粒聚结的机制，以实现对纳米级相的精确控制以及由放热能量诱导的晶粒聚结的形态。通过施加等离子体通过蚀刻硅衬底来产生放热能。通过调节等离子体功率和反应气体的流速，可以实现不同的蚀刻速率和轮廓，从而导致晶粒聚结的形态多种多样。平衡各向同性/各向异性衬底的蚀刻轮廓和蚀刻速率使得可以从衬底上同时释放2D纳米结构，并诱导由晶粒聚结产生的足够的表面张力，从而形成3D纳米结构。通过晶粒聚结获得了3D纳米结构的多种形态，并且已经提出并证明了实现自组装以产生所需3D纳米结构的策略。

在新窗口中打开图像