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梨花男子大学Dong-Wook Kim传授和Taeyoung Choi授教讲座告诉
公布人:王燚  公布工夫:2019-11-05   阅读次数:10

应一点彩票网刘树田传授约请,韩国梨花男子大学物理系Dong-Wook Kim传授和Taeyoung Choi授教克日来我校举行学术交换,迎接感兴味的师生加入,迎接故意展开深化互助(博士后或接见学者)的师生对接和讨论。

  

讲述一

  

问题:Fabrication and characterizations of mixed-dimensional nanostructures for optoelectronic device applications

讲述人:Dong-Wook Kim传授

讲座工夫:118 8:30-1000

讲座地址:先生流动中央331

讲座择要:

Researchers have fabricated heterostructures formed by integrating 2D layered materials with 0D, 1D, or 3D materials, to achieve enhanced optical absorption and photoexcited carrier separation. The physical properties of such mixed-dimensional nanostructures can be tuned by varying the material combinations, structures, and morphology. In my research group, particular attention has been given to heterostructures consisting of organic-inorganic semiconductors and 2D-materials. We prepared P3HT-coated Si-nanopillar (NP) arrays and studied spatial distribution of the surface photovoltage (SPV) in the samples using Kevin probe force microscopy. The Si-NPs with high aspect ratio exhibited broadband and omnidirectional antireflection effects. Furthermore, large SPV values appeared in the P3HT layers near the Si NPs under illumination of visible light. The optical resonance strongly concentrated incident light in the Si NPs due to the graded refractive index and Mie scattering, which increased the local density of the photo-generated carriers near the NPs. We also studied the optical characteristics of 2D MoS2 layers prepared on 3D Si-based nanostructures. The photoluminescence and Raman intensities of the MoS2 monolayers on SiO2 nanocones (NCs) are much greater than those on Si NCs. The leaky resonance mode in low refractive index SiO2 NC led to a large surface electric field intensity and increased the absorption of the MoS2 monolayers. Our works have demonstrated that the mixed-dimensional nanostructures are very helpful to improve not only the light trapping capability but also the carrier collection efficiency of the thin active layers grown on them.

  

讲述人简介:

image-20191105141132-1Prof. Dong-Wook Kim earned his B.S. (’95), M.S.(’97), and Ph.D.(’01) in Physics from Seoul National University in Korea. He have worked as a senior researcher at the Samsung Advanced Institute of Technology (’01-’05), a visiting scientist at the University of California, San Diego (’03-’05), and an assistant professor at Hanyang University at Ansan (’05-’08). In 2008, he joined in Department of Physics at Ewha Womans University in Korea as a faculty member. He is a member of editorial board of Scientific Reports, Current Applied Physics, and Journal of the Korean Physical Society. Selected honors include Outstanding Research Award from Applied Physics Division of Korean Physical Society (2018) and Outstanding Research Achievement Award from Ewha Womans University (2015).

  

讲述二

  

问题:Coherent Quantum control on atoms in trapped ion and ESR-STM 

讲述人:Taeyoung Choi传授

讲座工夫:118 10:00 -1130

讲座地址:先生流动中央331

讲座择要:

  

In recent years, understanding, controlling, and utilizing quantum systems for quantum information processing have been one of major research interests across fields of condensed matter and optical physics. In atomic molecular optics (AMO) physics, the ultracold trapped ion system has been one of leading and successful architectures for coherent quantum control since the qubits from the individual ions are highly pristine. This trapped ion architecture has demonstrated key ingredients for quantum computation and simulation. I will introduce basics, breakthroughs, and challenges of quantum computing in the trapped ion system.

Such quantum control has been also applied to condensed matter systems which may promise scalable Quantum information processing. In the second part of the talk, I will introduce a new approach to utilize excitonic physics for converting polarization of light into spin information. Here, we plan to investigate this research topic at atomic scale via scanning tunneling microscopy. Furthermore, I will present our recent effort for combining electron spin resonance technique with scanning tunneling microscopy (ESR-STM) and have successfully demonstrated controlling spin states of individual atoms on surfaces. This research effort can be utilized for characterizing magnetic interaction between atoms. With atomically precise position control and energy resolution, this ESR-STM demonstrates the possibility to utilize them for quantum sensing.

I would like to introduce our research contents and enhance the collaboration effort between HIT and EWHA.

  

讲述人简介:

image-20191105141132-2Prof. Taeyoung Choi earned his B.S. (’04) in Physics from Seoul National University in Korea and Ph.D. (’11) in Physics from Ohio State University in USA. He has worked as a post-doctoral researcher at the University of Maryland, College Park (’11-’14) – building 5 qubit quantum computer, a post-doctoral researcher at IBM Almaden Research Center, San Jose (’14-’17) – combining electron spin resonance with scanning tunneling microscopy, and an assistant professor at EWHA womans University (’17- present). He has published ~10 papers in prestige international journals such as Nature, Science, Nature Nanotechnology, Nature Physics, and PRL with more than 50 presentations in international conferences.