Wang Long-Yang et al 2008 Chinese Phys. Lett. 25 4154 doi:10.1088/0256-307X/25/11/086
Wang Long-Yang1, Wang Xiao-Ping1, Wang Li-Jun1 and Zhang Lei1
Show affiliationsBall-like nano-carhon thin films (BNCTs) are grown on Mo layers by microwave plasma chemical vapour deposition (MPCVD) system. The Mo layers are deposited on ceramic substrates by electron beam deposition method and are pretreated by ultrasonically scratching. The optimization effects of ultrasonically scratching pretreat-ment on the surface micro-structures of carbon films are studied. It is found from field-emission scanning electron microscope (FE-SEM) images and Raman spectra that the surface structures of the carbon films deposited on Mo pretreated are improved, which are composed of highly uniform nano-structured carbon balls with considerable disorder structures. Field emission (FE) measurements are carried out using a diode structure. The experimental results indicate that the BNCTs exhibit good FE properties, which have the turn on field of 1.56 V/μm, and the current density of 1.0mA/cm2 at electric field of 4.0 V/μm, the uniformly distributed emission site density from a broad well-proportioned emission area of 4 cm2 are also obtained. Linearity is observed in Fowler–Nordheim (F–N) plots in higher Geld region, and the possible emission mechanism of BNCTs is discussed.
79.70.+q Field emission, ionization, evaporation, and desorption
61.46.-w Structure of nanoscale materials
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, etc.)
68.55.-a Thin film structure and morphology
78.30.-j Infrared and Raman spectra
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
Condensed matter: electrical, magnetic and optical
Issue 11 (November 2008)
Received 8 August 2008
Wang Long-Yang et al 2008 Chinese Phys. Lett. 25 4154
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