|성명||손영우 교수 (Son, Young-Woo, Professor)|
|소속||Department of Physics, Ajou University, Suwon, Korea|
|주제||New faces of silicon|
|학력||1997, 2000, 2004, 서울대 물리학과 학, 석, 박사.|
2004 – 2007 미국 캘리포니아 주립대 버클리 캠퍼스 포스트 닥터
2007 – 2008. 08 건국대 서울 캠퍼스 물리학과 조교수
2008.09 – 현재 고등과학원 교수
Silicon (Si) is one of the most extensively studied materials owing to its significance to semiconductor science and technology.
In this talk, we will present two examples showing new and interesting physical properties in new forms of Si crystals.
First, based on a newly developed systematic ab initio materials searching strategy, we report a series of novel 2D Si crystals with unprecedented structural and electronic properties [1,2].
The new structures exhibit perfectly planar outermost surface layers of a distorted hexagonal network with their thicknesses varying with the atomic arrangement inside. Dramatic changes in electronic properties ranging from semimetal to semiconducting with indirect energy gaps and even to one with direct energy gaps are realized by varying thickness as well as by surface oxidation.
Second, based on first-principles study without any empirical parameter we show that the slightly doped Si24, a newly synthesized crystal, can provide an order-of-magnitude enhanced thermoelectric figure of merit at room temperature, compared with the cubic diamond phase of silicon .
We ascribe the enhancement to the intrinsic nanostructure formed by the nanopore array, which effectively hinders heat conduction while electric conductivity is maintained. In addition, we propose a practical strategy to further diminish the thermal conductivity without affecting electric conductivity by confining rattling guest atoms in the pores.
 K. Chae, D. Y. Kim, Y.-W. Son, 2D Materials 5, 025013 (2018).
 K. Chae, Y.-W. Son, in preparation (2018).
 K. Chae, S.-H. Kang, S.-M. Choi, D. Y. Kim, Y.-W. Son, Nano Lett. 18, 4748 (2018)