실리콘 지지와 뜬 그래핀 나노메쉬 내 포논 산란 특성의 정량적 연구

국문 초록 (Abstract)

본 연구는 포논(phonon) 평균자유행로(mean free path, MFP) 스펙트럼(spectrum) 분포 별 열전도 기여도를 이용하여, 실리콘(Si) 기질로 지지된 그래핀 나노메쉬(Si-GNM) 내 포논 산란 특성을 살폈다. 그래핀 나노메쉬(GNM) 내 포논 MFP에 대한 현상학적 접근(phenomenological approach)을 이용하여, Si-GNM와 뜬(suspended) GNM(Sus-GNM) 내 복잡한 포논 산란(scattering) 정도(n)를 표현할 수 있는 간단한 함수를 도입하고, 기존 연구에서 제시하지 못한 다공도(porosity, Ø) 증가에 따라 Si-GNM이 Sus-GNM 경우 보다 열전도율 억제 효과가 작아짐을 정량적으로 설명했다. 즉, 1.52%≤ Ø ≤ 9% 범위에서 Ø 가 커지면서 nsup/nsus=2.81에서 2.37로 감소함을 보였다. 본 연구 방법은 향후 GNM 기반 시스템에 대한 열 관리 및 열 제어 연구에 활용될 수 있다.

다국어 초록 (Multilingual Abstract)

In this study, the phonon scattering of a graphene nanomesh (Si-GNM) supported by a silicon substrate was investigated using the spectral thermal conductivity contribution of the phonon mean free path (MFP) at room temperature. Using the phenomenological approach to phonon MFPs in a GNM, we can express the complex scattering degree (n) in Si-GNM and suspended GNM (Sus-GNM) by proposing a simple form as a function of the hole spacing, phonon MFP, and porosity, showing a lower thermal conduction suppression effect than that of Sus-GNM as the porosity (Ø) increases, which has not been presented in previous studies. It was shown that the relative value of nsup/nsus is changed from 2.81 to 2.37 within the range of 1.52％≤Ø≤ 9％. This method can be applied to future thermal management and thermal control studies for GNM-based systems.

목차 (Table of Contents)

• 초록
• Abstract
• 1. 서론
• 2. GNM 포논 산란 해석 방법
• 3. GNM 내 포논 산란 정도 비교 결과
• 4. 결론
• 참고문헌(References)

참고문헌 (Reference)

1 진재식, "포논 평균자유행로 분포를 이용한 실리콘 포노닉 나노 구조에서의 포논 전달 예측 모델" 대한기계학회 42 (42): 221-228, 2018

2 Chiritescu, C., "Ultralow Thermal Conductivity in Disordered, Layered WSe2 Crystals" 315 (315): 351-353, 2007

3 Costescu, R. M., "Ultra-low Thermal Conductivity in W/Al2O3 Nanolaminates" 303 (303): 989-990, 2004

4 Feng, T., "Ultra-low Thermal Conductivity in Graphene Nanomesh" 101 : 107-113, 2016

5 Seol, J. H., "Two-Dimensional Phonon Transport in Supported Graphene" 328 (328): 213-216, 2010

6 Xiong, Z., "Thermal Transport in Supported Graphene Nanomesh" 10 (10): 9211-9215, 2018

7 Lee, W., "Thermal Conductivity Measurement of Holey Graphene as Porosity" 2018

8 Koniakhin, S. V., "Substrate-induced Reduction of Graphene Thermal Conductivity" 95 (95): 045418-, 2017

9 Kim, W., "Strategies for Engineering Phonon Transport in Thermoelectrics" 3 (3): 10336-10348, 2015

10 Feng, T., "Spectral Phonon Mean Free Path and Thermal Conductivity Accumulation in Defected Graphene : The Effects of Defect Type and Concentration" 91 (91): 224301-, 2015

11 Oh, J., "Significantly Reduced Thermal Conductivity and Enhanced Thermoelectric Properties of Single-and Bi-layer Graphene Nanomeshes with Sub-10 nm Neck-width" 35 : 26-35, 2017

12 Yu, J. -K., "Reduction of Thermal Conductivity in Phononic Nanomesh Structures" 5 (5): 718-721, 2010

13 Steele, B. C. H., "Materials for Fuel-cell Technologies" 414 (414): 345-352, 2001

14 Tien, C. L., "MICROSCALE ENERGY TRANSPORT" Taylor &Francis 3-94, 1998

15 Xu, X., "Length-dependent Thermal Conductivity in Suspended Single-layer Graphene" 5 : 3689-, 2014

16 Zhang, H., "Length Dependent Thermal Conductivity Measurements Yield Phonon Mean Free Path Spectra in Nanostructures" 5 : 9121-, 2015

17 Lee J., "Investigation of Phonon Coherence and Backscattering Using Silicon Nanomeshes" 8 : 14054-, 2017

18 Nobakht, A. Y., "Heat Flow Diversion in Supported Graphene Nanomesh" 123 : 45-53, 2017

19 Girit, Ç. Ö., "Graphene at the Edge : Stability and Dynamics" 323 (323): 1705-1708, 2009

20 Bai, J., "Graphene Nanomesh" 5 (5): 190-194, 2010

21 Lindsay, L, "Flexural Phonons and Thermal Transport in Graphene" 82 (82): 115427-, 2010

22 Ghosh, S., "Extremely High Thermal Conductivity of Graphene : Prospects for Thermal Management Applications in Nanoelectronic Circuits" 92 (92): 151911-, 2008

23 Ong, Z. -Y., "Effect of Substrate Modes on Thermal Transport in Supported Graphene" 84 (84): 075471-, 2011

24 Ravichandran, N. K., "Coherent and Incoherent Thermal Transport in Nanomeshes" 89 (89): 205432-, 2014

25 Tian, B., "Coaxial Silicon Nanowires as Solar Cells and Nanoelectronic Power Sources" 449 (449): 885-889, 2007

26 Bae, M.-H., "Ballistic to Diffusive Crossover of Heat Flow in Graphene Ribbons" 4 : 1734-, 2013