신소재공학과

Research Highlight



All our smart phones have shiny flat AMOLED displays. Behind each single pixel of these displays hide at least two silicon transistors which are mass-manufactured using laser annealing technologies. While the traditional methods to make them uses temperatures above 1,000°C, the laser technique reaches the same results at low temperatures even on plastic substrates (melting temperature below 300°C). Interestingly, a similar procedure can be used to generate crystals of graphene. Graphene is a strong and thin nano-material made of carbon, its electric and heat-conductive properties have attracted the attention of scientists worldwide.


Prof. Keon Jae Lee's research group at the Center for Multidimensional Carbon Materials within the Institute for Basic Science (IBS) and Prof. CHOI Sung-Yool's team at KAIST discovered graphene synthesis mechanism using laser-induced solid-state phase separation of single-crystal silicon carbide (SiC). This study, available on Nature Communications, clarifies how this laser technology can separate a complex compound (SiC) into its ultrathin elements of carbon and silicon. (http://www.nature.com/articles/ncomms13562)


Although several fundamental studies understood the effect of excimer lasers in transforming elemental materials like silicon, the laser interaction with more complex compounds like SiC has rarely been studied due to the complexity of compound phase transition and ultra-short processing time.

With high resolution microscope images and molecular dynamic simulations, scientists found that a single-pulse irradiation of xenon chloride excimer laser of 30 nanoseconds melts SiC, leading to the separation of a liquid SiC layer, a disordered carbon layer with graphitic domains (about 2.5 nm thick) on top surface and a polycrystalline silicon layer (about 5 nm) below carbon layer. Giving additional pulses causes the sublimation of the separated silicon, while the disordered carbon layer is transformed into a multilayer graphene.


"This research shows that the laser material interaction technology can be a powerful tool for next generation of two dimensional nanomaterials," said Prof. Keon. Prof. Choi added: "Using laser-induced phase separation of complex compounds, new types of two dimensional materials can be synthesized in the future." IBS Prof. Keon is affiliated with the School of Materials Science and Engineering, KAIST and Prof. Choi with the School of Electrical Engineering and Graphene Research Center, KAIST.



laser induced SiC.jpg

High-resolution transmission electron microscopy shows that after just one laser pulse of 30 nanoseconds, the silicon carbide (SiC) substrate is melted and separates into a carbon and a silicon layer. More pulses cause the carbon layer to organize into graphene and the silicon to leave as gas.



Nat.commun.fig1.png

Molecular dynamics simulates the graphene formation mechanism. The carbon layer on the top forms because the laser-induced liquid SiC (SiC (l)) is unstable.

No. Subject Author Date Views
» Making Graphene Using Laser-induced Phase Separation ADMINI 2016.12.07 2111
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Notice “Nature Materials” News & Views wrote by Prof. Sang Ouk Kim admin 2015.02.17 8961
Notice Academic Achievements & Related Awards admin 2015.02.17 6899
Notice Best Paper Award at 2014 Pan Pacific Microelectronic Symposium admin 2015.02.17 6791
Notice The Way towards Commercialization of Highly Efficient Nanogenerator admin 2015.02.17 7027
Notice The First Demonstration of Self-powered Cardiac Pacemaker admin 2015.02.17 6747
22 Equipment Development: “Hu:u” -New Concept Indoor Environmental Gauge file admin 2015.02.17 4802
21 Seon-Jin Choi, Jinsup Lee Prize Winner at the “9th 1nside” Edge International Thesis Competition from Samsung Electro-mechanics. file admin 2015.02.17 3356
20 Excellent Paper Award at the 2014 Conference on Next Generation Lithography file admin 2015.02.17 3291
19 3D Free Standing Structure Made of Graphene. file admin 2015.02.17 3249
18 One of 2013 KAIST Top 10 Representative R&D Outcomes. file admin 2015.02.17 3243
17 Prize Winner at 20th SAMSUNG Human Tech Paper award (2013) file admin 2015.02.17 3231
16 Intel Best Paper Award at Electronic Components and Technology Conference file admin 2015.02.17 3190
15 Review article from Prof. Sang Ouk, Kim group was published in 25th anniversary of Advanced Materials. file admin 2015.02.17 3180
14 New Nanocomposite Catalyst applied for Li-O2 Batteries with improved High-capacity and Long-cycle file admin 2015.02.17 3145
13 Mobile Sensor Array Platform & its Circuit Development. file admin 2015.02.17 3115
12 Excellent paper Award at the Optical Society of Korea. file admin 2015.02.17 3113
11 Grand Prize at the Dow Chemical Korea Award 2014 file admin 2015.02.17 3096
10 The Convergence New Technology Fair Silver Award file admin 2015.02.17 3068
9 Doctoral candidate Wan Heui Lee won the "Outstanding Poster Award" at The 2013 Spring Conference of the Kroean Institute of Metals and Materials", held in Jeju, Korea file admin 2015.02.17 3038