Institute of Solid State Physics, Ulm University, D-89069 Ulm, Germany.
Beilstein J Nanotechnol. 2013 Dec 12;4:886-94. doi: 10.3762/bjnano.4.100. eCollection 2013.
THE BASIC IDEA OF USING HEXAGONALLY ORDERED ARRAYS OF AU NANOPARTICLES (NP) ON TOP OF A GIVEN SUBSTRATE AS A MASK FOR THE SUBSEQUENT ANISOTROPIC ETCHING IN ORDER TO FABRICATE CORRESPONDINGLY ORDERED ARRAYS OF NANOPILLARS MEETS TWO SERIOUS OBSTACLES: The position of the NP may change during the etching process and, thus, the primary pattern of the mask deteriorates or is completely lost. Furthermore, the NP are significantly eroded during etching and, consequently, the achievable pillar height is strongly restricted. The present work presents approaches on how to get around both problems. For this purpose, arrays of Au NPs (starting diameter 12 nm) are deposited on top of silica substrates by applying diblock copolymer micelle nanolithography (BCML). It is demonstrated that evaporated octadecyltrimethoxysilane (OTMS) layers act as stabilizer on the NP position, which allows for an increase of their size up to 50 nm by an electroless photochemical process. In this way, ordered arrays of silica nanopillars are obtained with maximum heights of 270 nm and aspect ratios of 5:1. Alternatively, the NP position can be fixed by a short etching step with negligible mask erosion followed by cycles of growing and reactive ion etching (RIE). In that case, each cycle is started by photochemically re-growing the Au NP mask and thereby completely compensating for the erosion due to the previous cycle. As a result of this mask repair method, arrays of silica nanopillar with heights up to 680 nm and aspect ratios of 10:1 are fabricated. Based on the given recipes, the approach can be applied to a variety of materials like silicon, silicon oxide, and silicon nitride.
将具有一定形状的纳米粒子（NP）规则排列在基底上作为掩膜，随后进行各向异性刻蚀，以此来制备具有相应规则排列的纳米柱阵列，这一基本构想需要克服两个严重的障碍：一是在刻蚀过程中 NP 的位置可能会发生变化，从而导致掩膜的初始图案恶化或完全丢失；二是 NP 在刻蚀过程中会受到严重侵蚀，从而极大地限制了可实现的纳米柱高度。本工作提出了克服这两个问题的方法。为此，采用两亲嵌段共聚物胶束纳米光刻（BCML）技术将 Au NP（起始直径 12nm）阵列沉积在二氧化硅基底上。实验证明，蒸发的十八烷基三甲氧基硅烷（OTMS）层可以作为 NP 位置的稳定剂，通过无电光化学工艺可以将 NP 尺寸增加至 50nm。通过这种方式，可以获得最大高度为 270nm、纵横比为 5:1 的有序二氧化硅纳米柱阵列。或者，可以通过短时间的刻蚀步骤来固定 NP 的位置，该步骤对掩膜的侵蚀可忽略不计，随后再进行生长和反应离子刻蚀（RIE）循环。在这种情况下，每个循环都从光化学重新生长 Au NP 掩膜开始，从而完全补偿前一个循环的侵蚀。通过这种掩膜修复方法，可以制备出高度高达 680nm、纵横比为 10:1 的二氧化硅纳米柱阵列。基于所给出的方案，该方法可应用于多种材料，如硅、氧化硅和氮化硅。
