Y W Zhu et al 2005 Nanotechnology 16 88 doi:10.1088/0957-4484/16/1/018
Y W Zhu1,2, T Yu1, F C Cheong1, X J Xu3,4, C T Lim3,4, V B C Tan3,4, J T L Thong3,5 and C H Sow1,2,6
Show affiliationsUsing a simple method of direct heating of bulk copper plates in air, oriented CuO nanowire films were synthesized on a large scale. The length and density of nanowires could be controlled by growth temperature and growth time. Field emission (FE) measurements of CuO nanowire films show that they have a low turn-on field of 3.5–4.5 V µm−1 and a large current density of 0.45 mA cm−2 under an applied field of about 7 V µm−1. By comparing the FE properties of two types of samples with different average lengths and densities (30 µm, 108 cm−2 and 4 µm, 4 × 107 cm−2, respectively), we found that the large length–radius ratio of CuO nanowires effectively improved the local field, which was beneficial to field emission. Verified with finite element calculation, the work function of oriented CuO nanowire films was estimated to be 2.5–2.8 eV.
79.70.+q Field emission, ionization, evaporation, and desorption
81.20.-n Methods of materials synthesis and materials processing
68.55.-a Thin film structure and morphology
81.07.-b Nanoscale materials and structures: fabrication and characterization
73.30.+y Surface double layers, Schottky barriers, and work functions
Condensed matter: electrical, magnetic and optical
Surfaces, interfaces and thin films
Issue 1 (January 2005)
Received 25 August 2004, in final form 19 October 2004
Published 2 December 2004
Y W Zhu et al 2005 Nanotechnology 16 88
Ting Yu et al 2005 Nanotechnology 16 1238
Elena Kazatchenko et al 2006 J. Geophys. Eng. 3 386
M Ross and J S Story 1949 Rep. Prog. Phys. 12 291
J Keeling et al 2007 Semicond. Sci. Technol. 22 R1
Y A Urzhumov et al 2007 J. Opt. A: Pure Appl. Opt. 9 S322
Margareta Wallquist et al 2008 New J. Phys. 10 063005
Joële Viallon et al 2009 Metrologia 46 08013
Joële Viallon et al 2009 Metrologia 46 08014
Joële Viallon et al 2008 Metrologia 45 08005