| 학회 | 한국재료학회 |
| 학술대회 | 2014년 가을 (11/27 ~ 11/28, 대전컨벤션센터) |
| 권호 | 20권 2호 |
| 발표분야 | C. 에너지/환경 재료(Energy and Environmental Materials) |
| 제목 | Poly-crystalline IGZO superlattice films with atomic layer deposited ZnO buffer layer and their thermoelectric properties |
| 초록 | Low-dimensional nanostructures, such as superlattice, nanowire, and quantum-dot, induce the unexpected change of the density of state, effective mass of carriers, and phonon-dispersion relationship due to quantum confinement effect. In particular, it is known as new structures to improve the thermoelectric properties. In addition, the numerous interfaces in the superlattice decrease dramatically thermal conductivity due to increased phonon-scattering. In the previous study, we fabricated single-crystalline InGaO3(ZnO)m superlattice using epi-ZnO buffer layers and solution-based ZnO layers, which showed dramatically low thermal conductivity (1.11 Wm-1K-1). Furthermore, the introduction of grain-boundaries in InGaO3(ZnO)m superlattice can decrease the thermal conductivity due to increased interactions of phonon-grain boundaries. However, the loss of electron conduction by highly tilted grains should be avoided to maintain electrical conductivity. Thus, we tried to fabricate poly-crystal InGaO3(ZnO)m superlattice consisting of the gains with high c-axis preferred orientation to reduce thermal conductivity without the damage of electrical conductivity. In this survey, the ZnO buffer layers with different preferred orientations were used to fabricate poly-crystalline InGaO3(ZnO)m superlattice with high c-axis preferred orientation. The ZnO layers with 50 nm thickness were grown as buffer layers on c-sapphire substrates at different growth temperatures by thermal ALD. And then, amorphous IGZO layer was coated by sol-gel method and post-annealed at 900 °C for 9 hours. Finally, we fabricated a poly-crystalline InGaO3(ZnO)2 superlattice with high c-axis preferred orientation using ZnO buffer layer with high c-axis preferred orientation. This process showed moderate electrical conductivity and seebeck coefficient. Furthermore, it showed much lower thermal conductivity (0.6 Wm-1K-1), compared to both poly-crystalline InGaO3(ZnO)2 superlattice with low c-axis preferred orientation (1.6 Wm-1K-1) and single-crystalline InGaO3(ZnO)2 superlattice (1.11 Wm-1K-1). |
| 저자 | 조성운, 권용현, 백승기, 김예균, 신재희, 조형균 |
| 소속 | 성균관대 |
| 키워드 | oxide semiconductor; superlattice; thermal conductivity; atomic layer deposition |
