Abstract
Recently, ZnO nanowires have received wide attention. Existing fabrication approaches mainly focused on generating such nanowires with uniform density and length over a substrate. On the other hand, ZnO nanowires with gradients of density and length over a single substrate could make the corresponding devices have varied properties. Therefore, in this work, we developed a simple approach to generate ZnO nanowires of varied morphology on a common substrate. This was achieved by creating a boundary layer of non-uniform thickness which affected the amount of reactants reaching the surface during the growth. This was done by tilting the substrate relative to the incoming gas flow. Here, we first presented theoretical background of the critical idea, and then simulated the thicknesses of boundary layers for different substrate tilt angles. Finally, based on these theoretical and numerical investigations, we fabricated two types of surfaces, which had one- and two-tier wire structures, respectively.
Similar content being viewed by others
References
Conley JF, Stecker L, Ono Y (2005) Directed assembly of ZnO nanowires on a silicon substrate without metal catalyst using a patterned ZnO seed layer. Nanotechnology 16:292–296
Dalal SH, Baptista DL, Teo KBK, Lacerda RG, Jefferson DA, Milne WI (2006) Controllable growth of vertically aligned zinc oxide nanowires using vapor deposition. Nanotechnology 17:4811–4818
Fan Z, Lu JG (2005) Gate-refreshable nanowire chemical sensors. Appl Phys Lett 86:123510
Fan Z, Wang D, Chang P, Tseng W, Lu JG (2004) ZnO nanowire field-effect transistor and oxygen sensing property. Appl Phys Lett 85:5923–5925
Fang F, Zhao DX, Zhang JY, Shen DZ, Lu YM, Fan XW, Li BH, Wang XH (2008) The influence of growth temperature on ZnO nanowires. Mater Lett 62:1092–1095
Feng X, Feng L, Jin M, Zhai J, Jiang L, Zhu D (2004) Reversible super-hydrophobicity to super-hydrophilicity transition of aligned ZnO nanorod films. J Am Chem Soc 126:62–63
Gao PX, Song J, Liu J, Wang ZL (2007) Nanowire piezoelectric nanogenerators on plastic substrates as flexible power sources for nanodevices. Adv Mater 19:67–72
Granger RA (1995) Fluid mechanics. Dover Publications, New York
Greene LE, Law M, Tan DH, Montano M, Goldberger J, Somorjai G, Yang P (2005) General route to vertical ZnO nanowire arrays using textured ZnO seeds. Nano Lett 5:1231–1236
Hsu JWP, Tian ZR, Simmons NC, Matzke CM, Voigt JA, Liu J (2005) Directed spatial organization of zinc oxide nanorods. Nano Lett 5:83–86
Huang M, Wu Y, Feick H, Tran N, Weber E, Yang P (2001) Catalytic growth of zinc oxide nanowires by vapor transport. Adv Mater 13:113–116
Kind H, Yan H, Law M, Messer B, Yang P (2002) Nanowire ultraviolet photodetectors and optical switches. Adv Mater 14:158–160
Liu TY, Liao HC, Lin CC, Hu SH, Chen SY (2006) Biofunctional ZnO nanorod arrays grown on flexible substrates. Langmuir 22:5804–5809
Luo C, Xiang M, Heng X (2012) A stable intermediate wetting state after a water drop contacts the bottom of a microchannel or is placed on a single corner. Langmuir. doi:10.1021/la301348f
Pan ZW, Dai ZR, Wang ZL (2001) Nanobelts of semiconducting oxides. Science 291:1947–1949
Park WI, Gyu-Chul Y, Kim JW, Park SM (2003) Schottky nanocontacts on ZnO nanorod arrays. Appl Phys Lett 82:4358–4360
Park W, Kim JS, Yi GC, Bae MH, Lee HJ (2004) Fabrication and electrical characteristics of high-performance ZnO nanorod field-effect transistors. Appl Phys Lett 83:5052–5054
Schlichting H, Gersten K (2000) Boundary-layer theory. Springer, Berlin
Sze SM (2000) VLSI technology. McGraw Hill, New York
Vispute RD, Choopun S, Talyansk V, Sharma RP, Venkatesan T, He M, Tang X, Halpern JB, Spencer MG, Li YX, Salamanca-Riba LG, Iliadis AA, Jones KA (1998) Heteroepitaxy of ZnO on GaN and its implications for fabrication of hybrid optoelectronic devices. Appl Phys Lett 73:348–350
Wang ZL, Song J (2006) Piezoelectric nanogenerators based on zinc oxide nanowire arrays. Science 312:242–246
Wang X, Summers CJ, Wang ZL (2004) Large-scale hexagonal-patterned growth of aligned ZnO nanorods for nano-optoelectronics and nanosensor arrays. Nano Lett 4:423–426
Wang X, Song J, Liu J, Wang ZL (2007) Direct-current nanogenerator driven by ultrasonic waves. Science 316:102–105
Yang P, Yan H, Mao S, Russo R, Johnson J, Saykally R, Morris N, Pham J, He R, Choi H-J (2002) Controlled growth of ZnO nanowires and their optical properties. Adv Funct Mater 15:323–331
Zhang Y, Yu K, Jiang D, Zhua Z, Genge H, Luo L (2005) Zinc oxide nanorod and nanowire for humidity sensor. Appl Surf Sci 242:212–217
Acknowledgments
This work was supported in part through NSF-CMMI-0900595 grant.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Chakraborty, A., Liu, X., Wang, H. et al. Generation of ZnO nanowires with varied densities and lengths by tilting a substrate. Microsyst Technol 18, 1497–1506 (2012). https://doi.org/10.1007/s00542-012-1579-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00542-012-1579-9