표제지
목차
국문 요약 9
Abstract 10
1. 서론 11
2. 이론적 배경 13
2-1. PUF (Physical Unclonable Functions) 13
2-2. 화학 기상 증착된 그래핀 13
2-3. 그래핀 adlayer 형성 15
2-4. 그래핀 층수 특성화 16
2-5. 고분자 박막의 dewetting 19
3. 실험방법 21
3-1. 그래핀의 성장 및 전사 21
3-2. Dewetting과 O₂ plasma 식각을 통한 무작위 특성 제조 23
3-3. 이미지 분석 23
4. 결과 및 고찰 25
4-1. PUF tag를 제조하기 위한 adlayer-rich 그래핀의 APCVD 성장 27
4-2. PUF key를 제조하기 위한 adlayer-rich 그래핀의 LPCVD 성장 34
4-3. LPCVD 그래핀 기반의 PUF key 생성 및 성능 지수 분석 37
4-4. APCVD 그래핀 기반의 다색 PUF 태그의 제조 40
4-5. Dewetting 된 고분자 섬을 마스크로 사용하여 식각 된 APCVD 그래핀의 PUF 성능 지수 분석 45
4-6. 다색 라만 매핑 이미지를 활용한 인증 프로토콜 49
5. 결론 55
6. 참고문헌 56
Figure 1. Location of the second layer of graphene. (a) On-top growth. The second layer grows on top of the first layer. (b) Underlayer growth. The second layer grows... 15
Figure 2. Image of big graphite flake containing regions of many different thicknesses. The pictures were taken using (a) an optical microscope, (b) an atomic force microscope,... 16
Figure 3. Raman spectra of graphite and graphene. 17
Figure 4. graphene lattice structure and raman scattering (a) lattice structure of graphene, (b) reciprocal lattice, (c) Double-resonance raman scattering 18
Figure 5. Changes in G and 2D peaks depending on the number of layers of graphene. 19
Figure 6. Band structure and raman spectra of single layer graphene and double layer graphene 19
Figure 7. Effect of the thickness of the P2VP film on the size and separation distances of randomly positioned features. (a) SEM (top row), optical microscopy (second row), and... 21
Figure 8. PUF key generation process based on LPCVD graphene. (a) Schematic of binarized image generation process using OM image. (b) Scaling down and digital key generation. 25
Figure 9. Fabrication of APCVD graphene PUFs. (a) Schematic of the fabrication process. (b) OM image and the corresponding Raman mapping image. (c) Representative illustration for the authentication. 27
Figure 10. OM images of APCVD graphene samples grown under different flow rates of CH₄ precursor (Ar mixed gas) and H₂. The precursor flow rates and growth times were as follows:... 29
Figure 11. Graphene growth and adlayer formation on Cu foils with different surface morphologies. (a-c) AFM height images of Cu surfaces (a) Cu foil polished for 40s, root-mean-... 31
Figure 12. OM images of graphene prepared with different growth times on the unpolished foil (a, c, e, g) and the back side of the foil polished for 15 s (b, d, f, h) . The growth time was (a,... 32
Figure 13. Graphene adlayer formation and etching mechanism on Cu foils with different surface morphologies and chemical characteristics. (a) Etch hole formation in graphene on... 33
Figure 14. OM images of graphene samples grown on (a) the front side of Cu foils polished for 40 s, and (b) the back side of foils polished for 15 s. 34
Figure 15. OM and SEM images of LPCVD graphene samples grown in under various flow rates of the methane precursor and growth temperatures. The flow rates of the precursor and the... 36
Figure 16. OM images of the LPCVD graphene samples grown on Cu foils with different hydrogen-free pre-annealing times. The hydrogen-free pre-annealing times are (a) 0, (b) 1,... 37
Figure 17. Generation of keys and characterization of PUF performance metrics. (a) Digital key generation by binarization and size reduction of a graphene OM image. Grayscale... 39
Figure 18. Raman spectra of monolayer and bilayer regions of the graphene shown in Figure 11e. 40
Figure 19. OM images of P2VP films on graphene following thermal annealing at 250 and 270 ℃. The polymer films were prepared via spin-coating with solutions of P2VP prepared in... 42
Figure 20. Randomized features after the processes of dewetting, O₂ plasma etching, and washing on graphene films. The results are presented for three different thicknesses of P2VP... 43
Figure 21. Generation of Raman mapping images. (a) OM and (b) Raman mapping images of the same region. (c, d) Raman spectra for different numbers of graphene layers in the (c) broad... 45
Figure 22. Raman mapping images, their corresponding binary keys, and p-values 47
Figure 23. Generation of keys and calculation of PUF performance parameters. (a) Raman mapping image of the selected multilayer graphene substrate. (b, c) Binarization and size... 48
Figure 24. Stability of graphene PUFs. (a) Raman mapping image of the fabricated surface. (b, c) (b, c) Binary keys extracted from the samples were (b) stored in the ambient atmosphere for 6... 49
Figure 25. Authentication of graphene PUFs via a feature-matching algorithm. Step-by-step processing of an image for each color layer. 51
Figure 26. Authentication of graphene PUFs via a feature-matching algorithm. (a) Step-by- step processing of an image. (b) Feature matching for an image in the library. (c) Feature... 52
Figure 27. Authentication of graphene PUFs via a feature-matching algorithm. Feature matching for an image that is not in the library. 53
Figure 28. Authentication of graphene PUFs via a feature-matching algorithm. Feature matching for each color-layer image that is not in the library. 54