Structural, Electronic and Optical Properties of SiC Quantum Dots

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We Perform Density Functional Theory Calculations of the Hydrogen-Passivated Topological Silicon Carbide Quantum Dots (QDs) and Investigate their Structural, Electronic and Optical Properties. We Study Clusters Constructed from 3C-Sic with up to 8 Topological Shells, Corresponding to Diameters up to 2.2 Nm, Terminated Homogeneously with either Si-H or C-H Bonds. All Qds Exhibit Tensile Strain (1-5 %) within the Cluster Core. the Larger the Cluster, the Smaller the Strain in the Interior, however. Tensile Strain Increases from the inside of the Cluster towards the outside, Reaches a Maximum at the Second Layer below the Surface, and Vanishes only for Bonds Involving Surface Si or C Atoms. Quantum-Confinement Effects Are Observed for the Energy Gaps and Optical Gaps of SiC QDs. Size Has a Major Impact on the Absorption Edge in Comparison to a Weak Effect on the Photon Energy of the Spectra Maxima. Our Calculations Show that Surface Termination Plays a Crucial Role and Strongly Affects Energy Gaps, Optical Gaps and Optical Spectra. Orbitals around the HOMO-LUMO Gap Predominantly Localize within the Core of the Cluster, with Significant Contributions by the Surface for Si-H Terminated Clusters only.

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Periodical:

Journal of Nano Research (Volumes 18-19)

Pages:

77-87

DOI:

10.4028/www.scientific.net/JNanoR.18-19.77

Citation:

J. G. Wang and P. Kroll, "Structural, Electronic and Optical Properties of SiC Quantum Dots", Journal of Nano Research, Vols. 18-19, pp. 77-87, 2012

Online since:

July 2012

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$35.00

[1] G.L. Harris, Properties of Silicon Carbide (INSPEC, Institution of Electrical Engineers, 1995).

[2] J.S. Shor, L. Bemis, A.D. Kurtz, I. Grimberg, B.Z. Weiss, M.F. Macmillian, W.J. Choyke, Characterization of Nanocrystallites in Porous P-Type 6H-SiC, J. Appl. Phys. 76 (1994) 4045-4049.

DOI: 10.1063/1.357352

[3] F. Huisken, B. Kohn, R. Alexandrescu, S. Cojocaru, A. Crunteanu, G. Ledoux, C. Reynaud, Silicon carbide nanoparticles produced by CO2 laser pyrolysis of SiH4/C2H2 gas mixtures in a flow reactor, J. Nanoparticle Res. 1 (1999) 293-303.

DOI: 10.1023/a:1010081206959

[4] X.L. Wu, J.Y. Fan, T. Qiu, X. Yang, G.G. Siu, P.K. Chu, Experimental evidence for the quantum confinement effect in 3C-SiC nanocrystallites, Phys. Rev. Lett. 94 (2005).

DOI: 10.1103/physrevlett.94.026102

[5] J.Y. Fan, H.X. Li, J. Iiang, L.K.Y. So, Y.W. Lam, P.K. Chu, 3C-SiC nanocrystals as fluorescent biological labels, Small 4 (2008) 1058-1062.

DOI: 10.1002/smll.200800080

[6] J.Y. Fan, H.X. Li, W.N. Cui, Microstructure and infrared spectral properties of porous polycrystalline and nanocrystalline cubic silicon carbide, Appl. Phys. Lett. 95 (2009).

DOI: 10.1063/1.3180706

[7] L.T. Canham, Silicon Quantum Wire Array Fabrication by Electrochemical and Chemical Dissolution of Wafers, Appl. Phys. Lett. 57 (1990) 1046-1048.

DOI: 10.1063/1.103561

[8] C.B. Murray, D.J. Norris, M.G. Bawendi, Synthesis and Characterization of Nearly Monodisperse CdE (E = S, Se, Te) Semiconductor Nanocrystallites, J. Amer. Chem. Soc. 115 (1993) 8706-8715.

DOI: 10.1021/ja00072a025

[9] A.P. Alivisatos, Semiconductor clusters, nanocrystals, and quantum dots, Science 271 (1996) 933-937.

DOI: 10.1126/science.271.5251.933

[10] S.J. Xu, M.B. Yu, Rusli, S.F. Yoon, C.M. Che, Time-resolved photoluminescence spectra of strong visible light-emitting SiC nanocrystalline films on Si deposited by electron-cyclotron-resonance chemical-vapor deposition, Appl. Phys. Lett. 76 (2000).

DOI: 10.1063/1.126382

[11] J. Zhao, D.S. Mao, Z.X. Lin, B.Y. Jiang, Y.H. Yu, X.H. Liu, H.Z. Wang, G.Q. Yang, Intense short-wavelength photoluminescence from thermal SiO2 films co-implanted with Si and C ions, Appl. Phys. Lett. 73 (1998) 1838-1840.

DOI: 10.1063/1.122299

[12] X.T. Li, C.L. Shao, S.L. Qiu, F.S. Siao, W.T. Zheng, Z.M. Liu, O.M. Terasaki, Blue photoluminescence from SiC nanoparticles encapsulated in ZSM-5, Materials Letters 48 (2001) 242-246.

DOI: 10.1016/s0167-577x(00)00310-4

[13] Z.R. Huang, B. Liang, D.L. Jiang, S.H. Tan, Preparation of nanocrystal SiC powder by chemical vapour deposition, J. Mater. Science 31 (1996) 4327-4332.

DOI: 10.1007/bf00356457

[14] A. Takazawa, T. Tamura, M. Yamada, Porous Beta-Sic Fabrication by Electrochemical Anodization, Jap. J. Appl. Phys. Part 1 32 (1993) 3148-3149.

DOI: 10.1143/jjap.32.3148

[15] W.J. Choyke, L. Patrick, Absorption and Reflection Measurements on Cubic SiC, Bull. Am. Phys. Soc. 14 (1969) 417.

[16] I.V. Kityk, A. Kassiba, K. Plucinski, J. Berdowski, Band structure of large-sized SiC nanocomposites, Phys. Lett. A 265 (2000) 403-410.

DOI: 10.1016/s0375-9601(99)00912-3

[17] A. Kassiba, M. Makowska-Janusik, J. Boucle, J.F. Bardeau, A. Bulou, N. Herlin-Boime, Photoluminescence features on the Raman spectra of quasistoichiometric SiC nanoparticles: Experimental and numerical simulations, Phys. Rev. B 66 (2002) 155317.

DOI: 10.1103/physrevb.66.155317

[18] D.H. Feng, Z.Z. Xu, T.Q. Jia, X.X. Li, S.Q. Gong, Quantum size effects on exciton states in indirect-gap quantum dots, Phys. Rev. B 68 (2003) 035334.

DOI: 10.1103/physrevb.68.035334

[19] F.A. Reboredo, L. Pizzagalli, G. Galli, Computational engineering of the stability and optical gaps of SiC quantum dots, Nano Letters 4 (2004) 801-804.

DOI: 10.1021/nl049876k

[20] X.H. Peng, S.K. Nayak, A. Alizadeh, K.K. Varanasi, N. Bhate, L.B. Rowland, S.K. Kumar, First-principles study of the effects of polytype and size on energy gaps in SiC nanoclusters, J. Appl. Phys. 102 (2007) 024304.

DOI: 10.1063/1.2756047

[21] G. Kresse, J. Hafner, Abinitio Molecular-Dynamics for Liquid-Metals, Phys. Rev. B 47 (1993) 558-561.

[22] G. Kresse, J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54 (1996) 11169-11186.

DOI: 10.1103/physrevb.54.11169

[23] G. Kresse, J. Furthmüller, Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set, Comp. Mater. Science 6 (1996) 15-50.

DOI: 10.1016/0927-0256(96)00008-0

[24] P.E. Blöchl, Projector Augmented-Wave Method, Phys. Rev. B 50 (1994) 17953-17979.

DOI: 10.1103/physrevb.50.17953

[25] J.P. Perdew, Y. Wang, Accurate and Simple Analytic Representation of the Electron-Gas Correlation-Energy, Phys. Rev. B 45 (1992) 13244-13249.

DOI: 10.1103/physrevb.45.13244

[26] K. -H. Hellwege, O. Madelung, in: Landolt-Börnstein, New Series, (Springer-Verlag, Berlin, 1982).

[27] M.W. Zhao, Y.Y. Xia, F. Li, R.Q. Zhang, S.T. Lee, Strain energy and electronic structures of silicon carbide nanotubes: Density functional calculations, Phys. Rev. B 71 (2005) 085312.

DOI: 10.1103/physrevb.71.085312

[28] C. Persson, U. Lindefelt, Relativistic band structure calculation of cubic and hexagonal SiC polytypes, J. Appl. Phys. 82 (1997) 5496-5508.

DOI: 10.1063/1.365578

[29] C.H. Park, B.H. Cheong, K.H. Lee, K.J. Chang, Structural and Electronic-Properties of Cubic, 2H, 4H, and 6H Sic, Phys. Rev. B 49 (1994) 4485-4493.

DOI: 10.1103/physrevb.49.4485

[30] B. Adolph, G. VI, K. Tenelsen, F. Bechstedt, R. DelSole, Nonlocality and many-body effects in the optical properties of semiconductors, Phys. Rev. B 53 (1996) 9797-9808.

DOI: 10.1103/physrevb.53.9797

[31] B. Adolph, J. Furthmüller, F. Bechstedt, Optical properties of semiconductors using projector-augmented waves, Phys. Rev. B 63 (2001) 125108.

DOI: 10.1103/physrevb.63.125108

[32] H.C. Weissker, J. Furthmüller, F. Bechstedt, Optical properties of Ge and Si nanocrystallites from ab initio calculations. II. Hydrogenated nanocrystallites, Phys. Rev. B 65 (2002) 155382.

DOI: 10.1103/physrevb.65.155328

[33] H.C. Weissker, J. Furthmüller, F. Bechstedt, Structural relaxation in Si and Ge nanocrystallites: Influence on the electronic and optical properties, Phys. Rev. B 67 (2003) 245304.

DOI: 10.1103/physrevb.67.245304

[34] L.E. Ramos, J. Furthmüller, F. Bechstedt, Effect of backbond oxidation on silicon nanocrystallites, Phys. Rev. B 70 (2004) 033311.

DOI: 10.1103/physrevb.70.033311

[35] L.E. Ramos, J. Furthmüller, F. Bechstedt, Reduced influence of defects on oxidized Si nanocrystallites, Phys. Rev. B 71 (2005) 035328.

DOI: 10.1103/physrevb.71.035328

[36] K. Seino, F. Bechstedt, P. Kroll, Influence of SiO2 matrix on electronic and optical properties of Si nanocrystals, Nanotechnology 20 (2009) 135702.

DOI: 10.1088/0957-4484/20/13/135702

[37] D. Buttard, G. Dolino, C. Faivre, A. Halimaoui, F. Comin, V. Formoso, L. Ortega, Porous silicon strain during in situ ultrahigh vacuum thermal annealing, J. Appl. Phys. 85 (1999) 7105-7111.

DOI: 10.1063/1.370518

[38] The diameter of a cluster (its real shape is not a sphere, but a cubeoctahedron) is estimated from the radius of an equivalent, sphere, which volume equals the sum of volume increments VSi and VC for appropriate numbers of Si and C atoms, respectively. Volume increments per SiC unit (thus, VSi+VC) are taken from calculations of 3C-SiC. The ratio of VSi and VC is assumed to scale as the cube of their covalent radii. Finally, we use VC=5. 00 Å3 and VSi = 15. 98 Å3. Note that our definition of a radius for a cluster does not include a contribution from H atoms.

[39] W.Y. Ching, Y.N. Xu, P. Rulis, L.Z. Ouyang, The electronic structure and spectroscopic properties of 3C, 2H, 4H, 6H, 15R and 21R polymorphs of SiC, Mater. Sci. Eng. A 422 (2006) 147-156.

DOI: 10.1016/j.msea.2006.01.007

[40] S. Logothetidis, J. Petalas, Dielectric function and reflectivity of 3C-silicon carbide and the component perpendicular to the c axis of 6H-silicon carbide in the energy region 1. 5-9. 5 eV, J. Appl. Phys. 80 (1996) 1768-1772.

DOI: 10.1063/1.362975

[41] S. Albrecht, L. Reining, R. Del Sole, G. Onida, Ab initio calculation of excitonic effects in the optical spectra of semiconductors, Phys. Rev. Lett. 80 (1998) 4510-4513.

DOI: 10.1103/physrevlett.80.4510

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