Three dimensional atom probe tomography of nanoscale thin films, interfaces and particles
This dissertation demonstrates our research effort dedicating to extend the application of 3DAPT technique to various new materials including nanoscale monolayers, thin films, interfaces and particles for the first time. Novel sample designs and preparation methods are developed in order to broaden the application of the technique into fundamentally new areas such as monolayers, organic/biomaterials, polymers and nanoparticles analysis. Samples including surface oxide layers, ionic monolayers, alkanethiol monolayers, electrodeposited polymers, nanoparticles and metal-metal interfaces were successfully analyzed for the first time. A new sample configuration is proposed as using electrodeposited polymers to encapsulate nanoscale analytes and to coat conventional atom probe tips. This design enables the technique to image varieties of new materials which can not be analyzed before. Using this approach gold nanoparticles about 1.4 ~ 2 nm were observed in the three dimensional reconstruction images. The results demonstrate the ability of modern APT technique in the new areas and inspire the future discoveries.