[原分所演講] IAMS lecture on Dec 11, 3:30pm, Dr. Poe Lecture Hall, Prof. Po-Wen Chiu 邱博文教授
消息來源：原分所
截止日期：2014-12-11
Title: Twisting Graphene Superlattices
Speaker: Prof. Po-Wen Chiu (Department of Electrical Engineering & Institute of Electronic Engineering, National Tsing Hua University)
邱博文教授 (清華大學電機系及電子所)
Time: 3:30PM, December 11 (Thursday)
Place: Dr. Poe Lecture Hall, IAMS (本所浦大邦講堂 臺大校園內)
Contact: Dr. Kaito Takahashi 高橋開人博士
ABSTRACT:
Bi- and tri-layer graphene are intriguing materials in that its electronic structure can be altered by changing the stacking order or the relative twist angle, yielding a new class of low-dimensional carbon system. In this talk, I will show you the growth of bi- and tri-layer graphene using ambient pressure CVD on polycrystalline Cu. Controlling the nucleation in the early stage growth allows the constituent layers to form single hexagonal crystals. New Raman active modes and van Hove singularities at low energy sector are observed as a result of the formation of superlattice structure. I will show that it is possible to manipulate the electron-hole symmetry in the low-energy band structure of twisted bilayer graphene using a transverse electrical field. By applying a gate voltage to twisted bilayer with a critical rotation angle, electron resonance between the two saddle points can be turned on or off, depending on the electron-hole symmetry near the saddle points. The successful growth of single-crystal bi- and tri-layer graphene provides an attractive jumping-off point for systematic studies of interlayer coupling in misoriented few-layer graphene systems with well-defined geometry.
Speaker: Prof. Po-Wen Chiu (Department of Electrical Engineering & Institute of Electronic Engineering, National Tsing Hua University)
邱博文教授 (清華大學電機系及電子所)
Time: 3:30PM, December 11 (Thursday)
Place: Dr. Poe Lecture Hall, IAMS (本所浦大邦講堂 臺大校園內)
Contact: Dr. Kaito Takahashi 高橋開人博士
ABSTRACT:
Bi- and tri-layer graphene are intriguing materials in that its electronic structure can be altered by changing the stacking order or the relative twist angle, yielding a new class of low-dimensional carbon system. In this talk, I will show you the growth of bi- and tri-layer graphene using ambient pressure CVD on polycrystalline Cu. Controlling the nucleation in the early stage growth allows the constituent layers to form single hexagonal crystals. New Raman active modes and van Hove singularities at low energy sector are observed as a result of the formation of superlattice structure. I will show that it is possible to manipulate the electron-hole symmetry in the low-energy band structure of twisted bilayer graphene using a transverse electrical field. By applying a gate voltage to twisted bilayer with a critical rotation angle, electron resonance between the two saddle points can be turned on or off, depending on the electron-hole symmetry near the saddle points. The successful growth of single-crystal bi- and tri-layer graphene provides an attractive jumping-off point for systematic studies of interlayer coupling in misoriented few-layer graphene systems with well-defined geometry.