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제116회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Symmetry Reduction through Shape Transformation Involved in Seed Mediated Synthesis of Large 2D Bi2Se3

2015년 9월 3일 11시 31분 49초
INOR.P-132 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 15일 (목요일) 11:00~12:30
저자 및
Mukul Pradhan, 최희철1,*
기초과학연구원 CALDES, Korea
1포항공과대학교(POSTECH) 화학과, 기초과학연구원 CALDES, Korea
We report symmetry reduction phenomenon through shape transformation of circular to hexagonal disc involved in a seed mediated synthesis of large 2D Bi2Se3. However, previously reported Bi2Se3 nanostructures are limited to hexagonal nanoplates of small lateral diameter (~1-5 ?m lateral diameter). In this study, a simple and reliable method for the growth of large (~20-50 ?m lateral diameter and 10-15 nm thickness) circular as well as hexagonal disk of Bi2Se3 is reported in presence of ethylenediaminetetraacetic acid (EDTA). EDTA acts as a complexing agent for the bismuth precursor. During the growth process, small circular disk with higher symmetry gradually increases its size and finally converted to hexagonal disk having lower symmetry and then further growth is stopped. We can synthesize 2D Bi2Se3 with single grained as well as multiple grained crystals with stacked spirals by controlling the nucleation and growth process. We have characterized thoroughly the morphology and crystal structures of the synthesized new shapes and we have discussed the possible growth mechanisms in the context of control over surface chemistry and the nucleation stage. Raman spectroscopic analysis as well as AFM studies shows that the synthesized Bi2Se3 hexagonal disks are composed of 10-15 quintuple-layers. At the best of our knowledge this is the first in situ gradual addition methodology in presence of complexed precursor as well as face selective capping for slow over growth of seed for large 2D crystal synthesis.