Shi Zhiwei, Walker Amy V
Department of Materials Science and Engineering, RL 10, University of Texas at Dallas , 800 West Campbell Road, Richardson, Texas 75080, United States.
Langmuir. 2015 Feb 3;31(4):1421-8. doi: 10.1021/la5040239. Epub 2015 Jan 22.
We have developed a method by which to selectively and reproducibly deposit ZnO films on functionalized self-assembled monolayers (SAMs) using chemical bath deposition (CBD). The deposition bath is composed of zinc acetate and ethylenediamine. The deposition reaction pathways are shown to be similar to those observed for sulfides and selenides, even though ethylenediamine acts as both an oxygen source and a complexing agent. On -COOH terminated SAMs, Zn-carboxylate surface complexes act as nucleation sites for ion-by-ion growth, leading to the formation of adherent ZnO nanocrystallites. Cluster-by-cluster growth is also observed, which produces weakly adherent micrometer-sized ZnO crystallites. On -CH3 and -OH terminated SAMs, only micrometer-sized ZnO crystallites are observed because Zn(2+) does not complex with the SAM terminal group, preventing nucleation of the nanocrystalline phase. The application of either ultrasound ("sonication-assisted CBD") or stirring promotes ion-by-ion ZnO growth on -COOH terminated SAMs. Stirring produces smoother but less reproducible ZnO films than sonication-assisted CBD.
我们开发了一种方法，通过化学浴沉积（CBD）在功能化自组装单分子层（SAMs）上选择性且可重复地沉积ZnO薄膜。沉积浴由醋酸锌和乙二胺组成。尽管乙二胺既作为氧源又作为络合剂，但沉积反应路径显示与硫化物和硒化物所观察到的相似。在-COOH端基化的SAMs上，羧酸锌表面络合物作为离子逐个生长的成核位点，导致形成附着的ZnO纳米微晶。还观察到逐个簇生长，这产生了附着力弱的微米级ZnO微晶。在-CH3和-OH端基化的SAMs上，仅观察到微米级ZnO微晶，因为Zn(2+)不与SAM端基络合，从而阻止了纳米晶相的成核。超声处理（“超声辅助CBD”）或搅拌的应用促进了在-COOH端基化的SAMs上离子逐个生长的ZnO。与超声辅助CBD相比，搅拌产生的ZnO薄膜更光滑，但重现性较差。
