| 수용액 합성법의 2단계 성장온도 변화를 통한 ZnO 결정의 선택적 용해 현상 |
| 김정석, 채기웅1 |
호서대학교 신소재공학과
1호서대학교 BK21 대학원 반도체디스플레이공학과 |
| Selective Dissolution of ZnO Crystal by a Two-step Thermal Aging in Aqueous Solution |
| Jeong-Seog Kim, Ki-Woong Chae1 |
Department of Materials Science and Engineering, Hoseo University
1Department of BK21 Semiconductor & Display Engineering, Hoseo University |
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| ABSTRACT |
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ZnO hexagonal rods grown in aqueous solution can be changed into a tubular shape by two-step aging in the course of the growing process. In the first step, hexagonal ZnO rods is grown by aging at $90^{circ}C$ under a highly supersaturated aqueous solution giving rise to a fast precipitation rate. Meanwhile, during the second step aging at $60^{circ}C$ in the same aqueous solution, the hexagonal polar face (001) having higher surface energy than (010) side planes dissolves to minimize surface energy. Hence the flat (001) face changes to a craterlike face and the hexagonal rod length of ZnO decreases at an initial-stage of this step aging. The formation of the (101) wedge-type faces is ascribed to the resultant of competitive reactions between the dissolution of polar face minimizing the surface energy which is a dominant reaction at the initial stage and the precipitation reaction dissipating supersaturation. At a later stage of the second-step the reaction rates of these two processes in the aqueous solution become similar and the overall reaction is terminated. |
| Key words:
ZnO, Tubular structure, Crystal growth, Aqueous solution |
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