S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Mechanical Aerospace Engineering (기계항공공학부) Theses (Ph.D. / Sc.D._기계항공공학부)
Three Dimensional Assembly of Nanoparticles based on Electric-field Assisted Aerosol Lithography
전기장 보조 에어로졸 리소그래피를 이용한 3차원 나노입자 조립
- 공과대학 기계항공공학부
- Issue Date
- 서울대학교 대학원
- Nanoparticles; Ion Assisted Aerosol Lithography; Electrostatic lens effect; 3D printing; Electrified mask
- 학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2016. 2. 최만수.
- writing mode and 3D printing mode. By controlling the translation shape and speed, various shapes of nanoparticle structure were fabricated. We proposed new parameters called modified translation speed which could be used as the criteria for separating the 3D printing mode and writing mode.
mainly affect the electrostatic lens effect. Not only these controllable process parameters, the Brownian diffusion also does great effect on the electrostatic lens effect. Various 3D nanoparticle structure was fabricated based on understating the electrostatic lens effect. The charge transport inside the nanoparticle structure was investigated, and new nanoparticle deposition model was proposed and we validate the model by the experiment and the nanoparticle trajectory simulation.
To enhance the controllability of electrostatic lens effect, we propose new electrified mask method by applying an electric potential directly to the metal coated mask surface. The potential difference between the mask and the substrate generates electrostatic lens effect which makes charged nanoparticles deposited at the center of the mask opening. The electrostatic lens effect can be easily and precisely controlled by adjusting the potential difference between the mask and the substrate. Particle trajectories were calculated by solving the Langevin equation, and the resulting particle deposition profile was compared with the experimental results. Using this approach, a multi-material nanoparticle cluster array was fabricated by a sequential deposition of silver and copper nanoparticles after lateral translation of the mask
We have fabricate 3D nanoparticle structure by translating the mask in deposition process. Depending on the translation speed, nanoparticle deposition process was divided into 2 different modes
Nanoparticles has been considered as the fundamental building blocks in nanotechnology due to their excellent properties compared to bulk materials. In spite of great advances in fabricating functional nanoparticles having designed properties, there has been few researches for assembling them into desired shapes or placing at the exact location. Therefore, developing bottom-up based nanoparticle assembly technique is essential for practical use of nanoparticles.
The aim of this research is to develop a dynamic nanoparticle assembly technique which has nanoscale resolution and practicality. Ion Assisted Aerosol Lithography (IAAL) is aerosol based nanoparticle assembly technique which manipulate charged aerosol by controlling local electric field. In previously reported IAAL, the shape of nanoparticle structure was determined by the geometry of the pre patterned photoresist. In this article, we proposed the novel nanoparticle assembly method by which we can fabricate any shape of nanoparticle structure. With the new method, charged nanoparticles are deposited not through the fixed PR pattern nor the stencil mask, but movable stencil to assemble nanoparticles to form the intended shape.
The fundamental understanding of the electrostatic lens effect is essential to extend the boundary of IAAL method. Parameters affecting the charged nanoparticle motion was identified and their effect to focusing effect is studied for establishing a standard process of nanoparticle assembly. 3 factors
the mask-substrate distance, the deposition voltage, the ion accumulation voltage