Nanomechanical System Research Center, Korea Institute of Machinery and Materials, Daejeon, Republic of Korea.
Small. 2012 May 21;8(10):1563-9. doi: 10.1002/smll.201101960. Epub 2012 Feb 29.
A highly efficient, ultralarge-area nanolithography that integrates block-copolymer lithography with single-step ZnO nanoimprinting is introduced. The UV-assisted imprinting of a photosensitive sol-gel precursor creates large-area ZnO topographic patterns with various pattern shapes in a single-step process. This straightforward approach provides a smooth line edge and high thermal stability of the imprinted ZnO pattern; these properties are greatly advantageous for further graphoepitaxial block-copolymer assembly. According to the ZnO pattern shape and depth, the orientation and lateral ordering of self-assembled cylindrical nanodomains in block-copolymer thin films could be directed in a variety of ways. Significantly, the subtle tunability of ZnO trench depth enabled by nanoimprinting, generated complex hierarchical nanopatterns, where surface-parallel and surface-perpendicular nanocylinder arrays are alternately arranged. The stability of this complex morphology is confirmed by self-consistent field theory (SCFT) calculations. The highly ordered graphoepitaxial nanoscale assembly achieved on transparent semiconducting ZnO substrates offers enormous potential for photonics and optoelectronics.
本文提出了一种高效、大面积的纳米光刻技术，它将嵌段共聚物光刻技术与一步法 ZnO 纳米压印技术相结合。在紫外光辅助下，对感光性溶胶-凝胶前体进行压印，可以在一步法工艺中形成具有各种图案形状的大面积 ZnO 形貌图案。这种简单的方法提供了压印 ZnO 图案的光滑线边缘和高热稳定性；这些特性对于进一步的图形外延嵌段共聚物组装非常有利。根据 ZnO 图案的形状和深度，可以以各种方式对嵌段共聚物薄膜中自组装的圆柱形纳米畴的取向和横向有序进行导向。重要的是，纳米压印实现了 ZnO 沟槽深度的细微可调性，从而产生了复杂的分级纳米图案，其中表面平行和表面垂直的纳米圆柱阵列交替排列。自洽场理论（SCFT）计算证实了这种复杂形态的稳定性。在透明半导体 ZnO 衬底上实现的高度有序的图形外延纳米级组装为光子学和光电学提供了巨大的潜力。
