||Fabrication of Graphene Quantum Dots by Chemical Synthesis Process and Analyses of Optical and Electrical Properties
||Department of Mechanical Engineering
optical and electrical properties
In this review study, the emphasis has been given on the meticulous discussion of traditional and low cost methods as well as current development in preparation of modern quantum dots and the analyses of its optical and electrical properties. Graphene Quantum Dots (GQDs) inherit some of the useful properties of bulk graphene, which leads to its unique possession properties from bulk graphene due to the quantum confinement and edge effects. As an emerging material, GQDs presents a new open world for broad research area, from synthesis, explanation of properties to promising applications.
This thesis uses chemical synthesis process to produce the graphene quantum dots and then we transfer it to glass substrate. After we prepare the specimen then we perform experiments. We investigate the quality by Raman analysis. We also investigate the particles height and roughness of specimens. The optical properties such as transmittance and reflectance were analysed. The last experiment to perform was Hall Effect analyser for electrical properties.
The results show that specimens with high synthesizing temperature of 150°C have highest Raman intensity and high mean diameter of 6.12 nm. The advantage of high Raman intensity also helps in increasing the carrier mobility and concentration of the specimens. The specimen with highest temperature and highest surface roughness of 10.20 nm also has highest transmittance and lowest reflectance percentage. The optical properties are recognised to be size dependant and as the size of particle grows bigger the optical and electrical properties increase.
The specimens with increasing synthesizing temperature have increasing electrical properties because of free electrons that move to conduction band, which increases the number of holes and electrons in the concentration.
Chapter 1 Introduction 3
1.1 Preface 3
1.2 Literature Review 6
1.3 Research Motivation and Purposes 9
1.4 Thesis Writing Methodology 11
Chapter 2 Basic Theories for Graphene and Graphene Quantum Dots 12
2.1 Introduction to Graphene 12
2.2 Introduction to Graphene Quantum Dots 15
2.3 Applications of Graphene Quantum Dots 16
2.4 Properties of Graphene Quantum Dots 17
2.4.1 Optical Properties 17
2.4.2 Electronic Properties 17
2.5 Manufacturing and Preparation Method for GQDs 18
2.5.1 Top-Down Synthesis Processes 19
2.5.2 Bottom-Up Approach 22
2.6 Theories of Measuring Instrument 25
2.6.1 Transmission Electron Microscopy 25
2.6.2 Raman Spectroscopy 27
2.6.3 UV-Vis Spectroscopy 28
2.6.4 Atomic Force Microscopy (AFM) 29
2.6.5 Photoluminescence Spectroscopy 30
2.6.6 Hall Effect 31
Chapter 3 Experimental Details 41
3.1 Main Objective 41
3.2 Preparation of Specimen 45
3.2.1 Preparation of Graphene Oxide (GO) 47
3.2.2 Preparation of Graphene Quantum Dots (GQDs) 49
3.2.3 Preparation of Specimen with Glass Substrate 51
3.2.4 Preparation of Specimen for Electrical Properties 53
3.3 Optical Properties Measuring Instrument 54
3.3.1 Transmission Electron Microscopy (TEM) 54
3.3.2 Raman Spectrometer 55
3.3.3 Atomic Force Microscope (AFM) 56
3.3.4 UV/VIS Spectrometer 56
3.3.5 Analysis of Optical Band Gap 57
3.3.6 Photo Luminance Spectrometer 57
3.3.7 Figure of Merit (FOM) 58
3.4 Electrical Properties Measuring Instrument 58
3.4.1 Four-Point Probe / Hall Effect Measurement 58
Chapter 4 Results and Discussion 65
4.1 TEM Analyses 65
4.2 AFM Analyses 66
4.3 Raman Spectroscopy Analyses 68
4.4 UV/VIS Spectrometer Analyses 70
4.5 Figure of Merit (FOM) 72
4.6 Photo Luminance Spectrometer Analyses 72
4.7 Electrical Properties 73
4.7.1 Hall Effect Measurements Analyses 74
Chapter 5 Conclusion 110
5.1 Conclusion of Experimental Results 110
5.2 Future Works 111
 M. A. Manzoori, J. L. Hallaj, Chemiluminescence of graphene quantum dots and its application to the determination of uric acid. Journal of Luminescence, vol. 153, PP. 73-78, 2014.
 J. Sun, S. Yang, H. Shen, Z. Wang, T. Xu, L. Sun, H. Li, W. Chen, X. Jiang, G. Ding, Z. Kangm X. Xie, and M. Jiang, Ultra-High quantum Yield of Graphene Quantum Dots: Aromatic-Nitrogen Doping And Photoluminescence Mechanism. Particle & Particle Systems Characterization, vol. 32, PP. 434-440, 2014.
 D. Qu, M. Zheng, L. Zhang, H. Zhao, X. Jing, R. E. Haddad, H. Fan, Z. Sun, Formation mechanism and optimization of highly luminescent N-doped graphene quantum dots. Scientific Reports, vol. 4, PP. 1-9, 2014.
 H. Wang, T. Maiyalagan, X. Wang, Review on recent progress in nitrogen-doped graphene: synthesis, characterization, and its potential applications. Acs Catalysis, vol. 2, PP. 781-794, 2012.
 Y. Sun, S. Wang, C. Li, P. Luo, L. Tao, G. Shi, Large scale preparation of graphene quantum dots from graphite with tunable fluorescence properties. Physical Chemistry Chemical Physics, vol. 15, PP. 9907-9913, 2013.
 L. Wang, Y. Wang, T. Xu, H. Liao, C. Yao, Y. Liu, Z. Li, Z. Chen, D. Pan, L. Sun, M. Wu, Gram-scale synthesis of single-crystalline graphene quantum dots with superior optical properties. Nature Communications, vol. 5, PP. 1-9, 2014.
 A. Cao, Z. Liu, S. Chu, M. Wu, Z. Ye, Z. Cai., Y. Chang, S. Wang, Q. Gong, Y. Liu, A facile one-step method to produce graphene–CdS quantum dot nanocomposites as promising optoelectronic materials. Advanced Materials, vol. 22, PP. 103-106, 2010.
 S. Zhu, J. Zhang, C. Qiao, S. Tang, Y. Li, W. Yuan, Bo Li, Lu Tian, Fang Liu, R. Hu, H. Gao, H. Wei, H. Zhang, H. Sun, B. Yang, Strongly green-photoluminescent graphene quantum dots for bioimaging applications. Chemical Communications, vol. 47, PP. 6858-6860, 2011.
 S. Kim, S. Shin, T. Kim, H. Du, M. Song, C. Lee, K. Kim, S. Cho, D. H. Seo, S. SEO, Robust graphene wet transfer process through low molecular weight polymethylmethacrylate. Carbon, vol. 98, PP. 352-357, 2016.
 S. Zhu, J. Zhang, S. Tang, C. Qiao, L. Wang, H. Wang, X. Liu, Bo Li, Y. Li, W. Yu, X. Wang, H. Sun, B. Yang, Surface chemistry routes to modulate the photoluminescence of graphene quantum dots: From fluorescence mechanism to up conversion bioimaging applications. Advanced Functional Materials, vol. 22, PP. 4372-4370, 2012.
 R. Karmakar, Quantum Dots and it method of preparations - revisited. Prajnan O Sadhona, vol. 2, PP. 116-142, 2015.
 T. Saito, M. Wada, A. Kajita, Graphene interconnection and method of manufacturing the same. United States patent, vol. 117, PP. 885-905, 2015.
 Q. Yu, L. A. Jauregui, W. Wu, R. Colby, J. Tian, Z. Su, H. Cao, Z. Liu, D. Pandey, D. Wei, T. Chung, P. Peng, N. P. Guisinger, E. A. Stach, J. Bao, S. Pei, Y. P. Chen, Control and characterization of individual grains and grain boundaries in graphene grown by chemical vapour deposition. Nature Materials, vol. 10, PP. 443-449, 2011.
 A. C. Ferrari, J. C. Meyer, V. Scardaci, C. Casiraghi, M. Lazzeri, F. Mauri, S. Piscanec, D. Jiang, K. S. Novoselov, S. Roth, A. K. Geim, Raman spectrum of graphene and graphene layers. Physical Review Letters, vol. 97, PP. 1-4, 2006.
 Q. Li, B. Guo, J. Yu, J. Ran, B. Zhang, H. Yan, J. Gong, Highly efficient visible-light-driven photocatalytic hydrogen production of CdS-cluster-decorated graphene nanosheets. Journal of The American Chemical Society, vol. 133, PP. 10878-10884, 2011.
 G. Prakash, M. A. Capano, M. L. Bolen, D. Zemlyanov, R. G. Reifenberger, AFM study of ridges in few-layer epitaxial graphene grown on the carbon-face of 4H–SiC (0001¯). Carbon, vol. 48, PP. 2383-2393, 2010.
 S. Tong, X.-na Liu, Xi-m. Bao. Study of photoluminescence in nanocrystalline silicon/amorphous silicon multilayers. Applied Physics Letters, vol. 66, PP. 469-471, 1995.
 B. Zhang, C.-Y. Liu, Y. Liu. A novel one step Approach to Synthesize Fluorescent Carbon Nanoparticles. European Journal of Inorganic Chemistry, vol. 2010, PP. 4411-4414, 2010.
 X. Li, W. Cai, J. An, S. Kim, J. Nah, D. Yang, R. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, R. S. Ruoff, Large Area Synthesis of High Quality and Uniform Graphene films on Copper Foils. Science, vol. 324, PP.1312-1314, 2009.
 F. Bonaccorso, Z. Sun, T. Hasan, A. C. Ferrari, Graphene photonics and optoelectronics. Nature Photonics, vol. 4, PP. 611-622, 2010.
 P. T. Araujo, M. Terrones, M. S. Dresselhaus, Defects and impurities in grapheme-like materials. Materialstoday, vol. 15, PP. 98-109, 2012.
 J. Zhao, S. Pei, W. Ren, L. Gao, H.-M. Cheng, Efficient preparation of large-area Graphene oxide sheets for transparent conductive films. ACS Nano, vol. 4, PP. 5245-5252, 2010.
 L.L. Li, J. Ji, R. Fei, C.Z. Wang, Qian Lu, J.‐R. Zhang, L.‐P. Jiang, J.‐J. Zhu, A facile microwave avenue to electrochemiluminescent two‐color graphene quantum dots. Advanced Functional Materials, vol. 22, PP. 2971-2979, 2012.
 M. Kim, N.S. Safron, E. Han, M. S. Arnold, P. Gopalan, Fabrication and characterization of large-area, semiconducting nanoperforated graphene materials. Nano Letters, vol.10, PP. 1125-1131, 2010.
 S. Hang, Z. Moktadir, H. Mizuta, Raman study of damage extent in graphene nanostructures carved by high energy helium ion beam. Carbon, vol. 72, PP. 233-241, 2014.
 H. Cheng , Y. Zhao , Y. Fan , X. Xie , L. Qu ,G. Shi . Graphene-quantum-dot assembled nanotubes: a new platform for efficient Raman enhancement. Acs Nano, vol. 6, PP. 2237-2244, 2012.
 L. Li, G. Wu, G. Yang, J. Peng, J. Zhao, J-J. Zhu, Focusing on luminescent graphene quantum dots: current status and future perspectives. Nanoscale, vol. 5, PP. 4015-4039, 2013.
 T. Fan, W. Zeng, W. Tang, C. Yuan, S. Tong, K. Cai, Y. Liu, W. Huang, Y. Min, A. J. Epstein, Controllable size-selective method to prepare graphene quantum dots from graphene oxide. Nanoscale Research Letters, vol. 10, PP. 1-8, 2015.
 Y. Zhou, Z. B. Qu, Y. Zeng, T. Zhou, G. Shi, A novel composite of graphene quantum dots and molecularly imprinted polymer for fluorescent detection of paranitrophenol. Biosensors and Bioelectronics, vol. 52, PP. 317-323, 2014.
 M. Merisalu, T. Kahro, J. Kozlova, A. Niilisk, A. Nikolajev, M. Marandi, A. Floren, H. Alles, V. Sammelselg, Graphene–polypyrrole thin hybrid corrosion resistant coatings for copper. Synthetic Metals, vol. 200, PP. 16-23, 2015.
 Y. Dong, Q. Liu, Q. Zhou, Corrosion behavior of Cu during graphene growth by CVD. Corrosion Science, vol. 89, PP. 214-219, 2014.
 P. T. K. Loan, D. Wu, C. Ye, X. Li, Q. Wei, Li Fu, A. Yu, L.-J. Li, C.-T. Lin, Hall effect biosensors with ultraclean graphene film for improved sensitivity of label-free DNA detection. Biosensors and Bioelectronics, vol. 99, PP. 85-91, 2018.
 R. Pearce, T. Iakimov, M. Andersson, L. Hultman, A. Lloyd Spetz, R. Yakimova, Epitaxially grown graphene based gas sensors for ultra sensitive NO2 detection. Sensors and Actuators B: Chemical, vol. 155, PP. 451-455, 2011.
 F. Schedin, A. K. Geim, S. V. Morozov, E. W. Hill, P. Blake, M. I. Katsnelson, K. S. Novoselov, Detection of individual gas molecules adsorbed on graphene. Nature Materials, vol. 6, PP. 652-655, 2017.
 J. L. Tedesco, B. L. VanMil1, R. L. Myers-Ward, J. M. McCrate, S. A. Kitt, P. M. Campbell, G. G. Jernigan, J. C. Culbertson, C. R. Eddy, Jr., D. K. Gaskill, Hall effect mobility of epitaxial graphene grown on silicon carbide. Applied Physics Letters, vol. 95, PP. 1-3, 2009.