Oh Yong-Jun, Ross Caroline A, Jung Yeon Sik, Wang Yang, Thompson Carl V
Advanced Materials Science and Engineering Division, Hanbat University, Korea.
Small. 2009 Apr;5(7):860-5. doi: 10.1002/smll.200801433.
Self-assembled cobalt particle arrays are formed by annealing, which cause agglomeration (dewetting) of thin Co films on oxidized silicon substrates that are topographically prepatterned with an array of 200-nm-period pits. The Co nanoparticle size and uniformity are related to the initial film thickness, annealing temperature, and template geometry. One particle per 200-nm-period pit is formed from a 15-nm film annealed at 850 degrees C; on a smooth substrate, the same annealing process forms particles with an average interparticle distance of 200 nm. Laser annealing enables templated dewetting of 5-nm-thick films to give one particle per pit. Although the as-deposited films exhibit a mixture of hexagonal close-packed and face-centered cubic (fcc) phases, the ordered cobalt particles are predominantly twinned fcc crystals with weak magnetic anisotropy. Templated dewetting is shown to provide a method for forming arrays of nanoparticles with well-controlled sizes and positions.
通过退火形成自组装钴颗粒阵列，这会导致在氧化硅衬底上的钴薄膜发生团聚（去湿），该氧化硅衬底预先在地形上用一系列周期为200纳米的凹坑进行了图案化处理。钴纳米颗粒的尺寸和均匀性与初始薄膜厚度、退火温度和模板几何形状有关。每200纳米周期的凹坑中由一个15纳米厚的薄膜在850摄氏度退火形成一个颗粒；在光滑衬底上，相同的退火过程形成平均颗粒间距为200纳米的颗粒。激光退火能够使5纳米厚的薄膜进行模板化去湿，从而每个凹坑形成一个颗粒。尽管沉积态薄膜呈现出六方密堆积和面心立方（fcc）相的混合，但有序的钴颗粒主要是具有弱磁各向异性的孪晶fcc晶体。模板化去湿被证明是一种形成尺寸和位置得到良好控制的纳米颗粒阵列的方法。
