Research
Atomic Layer Deposition (ALD) 原子层沉积技术
The growth and application of thin films grown by Atomic Layer Deposition (ALD). Atomic layer deposition (ALD) can be considered to be a special kind of chemical vapor deposition (CVD) which can grow films with high uniformity and excellent conformity. In our work, we paid a lot of attention to the use of the ALD technique to grow ZnO, TiO2, Al2O3 and HfO2 films and heterogeneous multilayers, so that we have built the basic ideas about growing the different films for different devices.
For growing the single material film, we have obtained new insights into the growth mechanisms, and the detailed effects of growth parameters on film characteristics like film growth rate, the surface structure evolution, density changes as a function of deposition temperature and impurity distribution. The highlight of my work is that we have successfully used an isotopic method to trace the film growth and identify the impurity origin. For example, the hydrogen from water oxidant. We sought electrochemical means to deliberately invoke proton transport in the multilayer.
Topic：
· Atomic layer deposition
· Ion Beam analysis
· Impurity detection
· Stable isotopic tracing
· Film growth mechanisms
· Electrochemical testing
· Aqueous proton batteries
Hydrogen retention (氢滞留) in material
One of the key problems in controllable nuclear fusion reaction researches is the retention of hydrogen in the material. The isotope of hydrogen Deuterium and Tritium acting as fuel in the nuclear fusion reaction will partially retent in the environmental materials, leading to inefficient usage of fuel.
In our study, Thermal Desorption Spectrometry (TDS) is used to heat up sample materials at certain ramp rates in an ultra-high vacuum (UHV) chamber connected to a Mass Spectrometry that collects the escaped elements from the heated sample. By analyzing the spectra, the retention sites of elements shall be determined. With this information, we could improve the design of materials for better storage of fuels for retention-affected cells.
Topic：
· Hydrogen retention
· Thermal desorption spectrometry
· Deuterium Isotopic analysis
· Zirconium, Ferritic steel
Nanopores on amorphous alumina in acidic electrolyte
The formation of nanopores on aluminum oxide by anodizing in certain acidic electrolytes has been discovered thanks to the micro-observation technologies since year 2000. The anodic nanoporous alumina is known as a tool for porous film formation and is widely used in industry with further potential, but the formation mechanism is still under discussion. In our studies, oxygen isotope 18O and heavy (relatively immobile) element Arsenate are used as tracers in the studies of nanopores formation mechanism in anodized alumina. Characterization of samples is performed with Ion Beam Analysis (IBA) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Transmission Electron Microscopy. With these technologies, the content and profiling of the tracer elements can be analyzed so we can tell what happens during the formation of the nanopores.
Topic：
· Aluminum
· Anodization
· Nanopores
· Isotope tracer