C Li

Stable, self-ballasting field emission from zinc oxide nanowires grown on an array of vertically aligned carbon nanofibers

A structure composed of zinc oxide nanowires (ZNWs) grown hydrothermally on an array of vertically aligned carbon nanofibers (CNFs) was fabricated and its field emission properties determined and compared with bare CNF arrays. The combination produced a macroscopic turn-on field of 1.2 V/μm which was found to be the lowest reported from ZNWs deposited on a two-dimensional substrate and much less than the equivalent CNFs array (5.2 V/μm). Crucially, field emission was found to be much more stable at higher pressures of 5×10−6 mbar without exhibiting current degradation for a fixed external field, while emitting with a current density of 1 mA/cm2, the current density typically required for backlighting and field emission displays. We propose a self-ballasting mechanism, in which the low carrier density in the zinc oxide prevents current runaway in the presence of adsorbed species.

Fabrication and field emission properties of regular hexagonal flowerlike ZnO nanowhiskers

Regular hexagonal flowerlike zinc oxide (ZnO) whiskers have been fabricated on the indium tin oxide electrodes with glass panel. A relatively simple hydrothermal growth process of low temperature is developed. The field emission properties of the flowerlike ZnO nanowhiskers have a low field emission threshold voltage (2.2V∕μm at a current density of 0.1μA∕cm2) and a high current density of 1mA∕cm2 at an applied field of 6.3V∕μm. The hydrothermal process method and good field emission properties indicate their potential application in field emission display device with glass panels.

Angular distribution of field emitted electrons from vertically aligned carbon nanotube arrays

Angular field emission (FE) properties of vertically aligned carbon nanotube arrays have been measured on samples grown by plasma enhanced chemical vapor deposition and characterized by scanning electron microscope and I-V measurements. These properties determine the angular divergence of electron beams, a crucial parameter in order to obtain high brilliance FE based cathodes. From angular distributions of the electron beam transmitted through extraction grids of different mesh size and by using ray-tracing simulations, the maximum emission angle from carbon nanotube tips has been determined to be about ± 30° around the tube main axis.

Publisher’s Note: “Angular distribution of field emitted electrons from vertically aligned carbon nanotube arrays” [Appl. Phys. Lett. 100, 053116 (2012)]

(Received 27 April 2012; accepted 11 June 2012; published online 21 June 2012)[http://dx.doi.org/10.1063/1.4730979]This article was originally published online on 2 February 2012 with co-author Y. Zhang name linked to affiliation No. 4instead of No. 3.All online versions of the article were corrected on 4 May 2012.