Rapid growth of ZnO hexagonal tubes by direct microwave heating

Abstract

Zinc oxide hexagonal tubular crystals were synthesized by direct microwave heating from ZnO powders within 5 min without any metal catalysts or transport agents. ZnO source materials were evaporated from the high-temperature zone in an enclosure, and crystals were grown on the self-source substrate in an appropriate condition. The ZnO vapor formed in the high-temperature zone can deposit and grow on the powders located in the low-temperature zone to form crystals. The scanning electron microscopy (SEM) reveals that these products are hexagonal tube crystals with 80 μm in diameter and 250 μm in length, having a well faceted end and side surface. A possible growth mechanism and the influence of reaction temperature on the formation of crystalline ZnO hexagonal tubes were presented. The photoluminescence (PL) exhibits strong ultraviolet emission at room temperature, indicating the potential applications in short-wave light-emitting photonic devices.

Keywords

ZnO crystal / microwave heating / vapor growth / photoluminescence (PL)

References

[1] Iijima S. Helical microtubules of graphitic carbon. Nature, 1991, 354(7): 56.

[2] Kurt R., Bonard J.M., Karimi A. Structure and field emission properties of decorated C/N nanotubes tuned by diameter variations. Thin Solid Films, 2001, 398–399, 193.

[3] Thiyagarajan P., Kottaisamy M., Rama N., et al. White light emitting diode synthesis using near ultraviolet light excitation on zinc oxide-silicon dioxide nanocomposite. Scripta Mater., 2008, 59(7): 722.

[4] Sonawane Y.S., Kanade K.G., Kale B.B. Electrical and gas sensing properties of self-aligned copper-doped zinc oxide nanoparticles. Mater. Res. Bull., 2008, 43(10): 2719.

[5] Lin H.B., Cao M.S., Zhao Q.L., et al. Mechanical reinforcement and piezoelectric properties of nanocomposites embedded with ZnO nanowhiskers. Scripta Mater., 2008, 59(7): 780.

[6] Liu J.P., Huang X.T. A low-temperature synthesis of ultraviolet- light-emitting ZnO nanotubes and tubular whiskers. J. Solid State Chem., 2006, 179(3): 843.

[7] Jung J.Y., Park N.K., Han S.Y., et al. The growth of the flower-like ZnO structure using a continuous flow microreactor. Curr. Appl. Phys., 2008, 8(8): 720.

[8] Umar A., Choi Y.J., Suh E.K., et al. Evolution of ZnO nanostructures by non-catalytic growth process on steel alloy substrate: structural and optical properties. Curr. Appl. Phys., 2008, 8(6): 798.

[9] Dhanaraj G., Dudley M., Bliss D., et al. Growth and process induced dislocations in zinc oxide crystals. J. Cryst. Growth, 2006, 297(1): 74.

[10] Tang Y.Y., Luo L.J., Chen Z.G., et al. Electrodeposition of ZnO nanotube arrays on TCO glass substrates. Electrochem. Commun., 2007, 9(2): 289.

[11] Kong X.H., Sun X.M., Li X.L., et al. Catalytic growth of ZnO nanotubes. Mater. Chem. Phys., 2003, 82(3): 997.

[12] Yuan X.L., Zhang B.P., Niitsum J., et al. Cathodoluminescence characterization of ZnO nanotubes grown by MOCVD on sapphire substrate. Mater. Sci. Semicond. Process., 2006, 9(1–3): 146.

[13] Menezes R.R., Kiminami R.H.G.A. Microwave sintering of alumina-zirconia nanocomposites. J. Mater. Process. Technol., 2008, 203(1): 513.

[14] Fang C.Y., Wang C.P., Polotai A.V., et al. Microwave synthesis of nano-sized barium titanate. Mater. Lett., 2008, 62(3): 2551.

[15] Xu X.D., Zhang M., Feng J., et al. Shape-controlled synthesis of single-crystalline cupric oxide by microwave heating using an ionic liquid. Mater. Lett., 2008, 62(17–18): 2787.

[16] Zhu J.J., Zhu J.M., Liao X.H., et al. Rapid synthesis of nanocrystalline SnO₂ powders by microwave heating method. Mater. Lett., 2002, 53(1–2): 12.

[17] Hart J.N., Menzies D., Cheng Y.B., et al. A comparison of microwave and conventional heat treatments of nanocrystalline TiO₂. Sol. Energy. Mater. Sol. Cells, 2007, 91(1): 6.

[18] Zhou X.F., Hu Z.L., Chen Y., et al. Microscale sphere assembly of ZnO nanotubes. Mater. Res. Bull., 2008, 43(10): 2790.

[19] Yu D.Q., Hu L.Z., Li J., et al. Catalyst-free synthesis of ZnO nanorod arrays on InP (001) substrate by pulsed laser deposition. Mater. Lett., 2008, 62(25): 4063.

[20] Lin C.H., Chang H.Y., Lin I.N. Densification behavior of Y3Fe5O12 materials prepared by microwave sintering process. IEEE Trans. Magn., 1997, 33(6): 3415.

[21] Hejazi S.R., Madaah Hosseini H.R. A diffusion- controlled kinetic model for growth of Au-catalyzed ZnO nanorods: theory and experiment. J. Cryst. Growth, 2007, 309(1): 70.

[22] Wang J., Sha J., Yang Q., et al. Carbon-assisted synthesis of aligned ZnO nanowires. Mater. Lett., 2005, 59(21): 2710.

[23] Cheng H.B., Cheng J.P., Zhang Y.J., et al. Large-scale fabrication of ZnO micro-and nano-structures by microwave thermal evaporation deposition. J. Cryst. Growth, 2007, 299(1): 34.

[24] Vanheusden K., Seager C.H., Warren W.L., et al. Correlation between photoluminescence and oxygen vacancies in ZnO phosphors. Appl. Phys. Lett., 1996, 68(3): 403.