Great improvement in adhesion and uniformity of carbon nanotube field emitters through reactive nanometer-scale SiC fillers

Abstract We developed highly adhesive uniform field emitters (FEs) from carbon nanotube (CNT) pastes by reacting nanometer-scale silicon carbide (SiC) fillers on a Kovar substrate at a high temperature in vacuum. The reaction of SiC on Kovar results in significant morphological changes at the substrate–composite interface along with moderate Si diffusion into the substrate, enhancing adhesion of CNT FEs to the substrate greatly. Furthermore, a post surface-treatment after the reaction of SiC fillers results in very uniform CNT FEs over an entire emitter pattern of several hundred micrometers. The strongly enhanced adhesion and uniformity of the CNT FEs, in turn, give stable and reliable field emission even at a high current density. The applicability of the SiC/CNT FEs was evaluated in super-miniature X-ray tubes where any detachment of materials including outgassing from the inner side of the tubes should be avoided. The smallest super-miniature CNT X-ray tube to date, with an outer diameter of 2.0 mm, shows good operation with X-ray imaging at an anode voltage of above 25 kV, confirming almost no outgassing and strong substrate adhesion of the CNT FEs.

[1]  C. Leinenbach,et al.  High-temperature processable carbon–silicate nanocomposite cold electron cathodes for miniature X-ray sources , 2013 .

[2]  Iijima,et al.  Heterostructures of single-walled carbon nanotubes and carbide nanorods , 1999, Science.

[3]  Otto Zhou,et al.  Rapid and reproducible fabrication of carbon nanotube AFM probes by dielectrophoresis. , 2005, Nano letters.

[4]  P. Kruit,et al.  Stable field emission from W tips in poor vacuum conditions , 2003 .

[5]  T. Chou,et al.  Fabrication and characterization of reaction bonded silicon carbide/carbon nanotube composites , 2005 .

[6]  Lili Jiang,et al.  Controlled Synthesis of Large‐Scale, Uniform, Vertically Standing Graphene for High‐Performance Field Emitters , 2013, Advanced materials.

[7]  Yann Lamy,et al.  Controlled Mounting of Individual Multiwalled Carbon Nanotubes on Support Tips , 2003 .

[8]  F. Okuyama,et al.  Miniature x-ray tubes: current state and future prospects , 2013 .

[9]  Sang Jin Lee,et al.  The high contrast ratio and fast response time of a liquid crystal display lit by a carbon nanotube field emission backlight unit , 2008, Nanotechnology.

[10]  D. Jaffray,et al.  Design and fabrication of carbon nanotube field-emission cathode with coaxial gate and ballast resistor. , 2013, Small.

[11]  Jiangtao Hu,et al.  Controlled growth and electrical properties of heterojunctions of carbon nanotubes and silicon nanowires , 1999, Nature.

[12]  John Robertson,et al.  Growth process conditions of vertically aligned carbon nanotubes using plasma enhanced chemical vapor deposition , 2001 .

[13]  T. Feng,et al.  A comparative study of field emission properties of carbon nanotube films prepared by vacuum filtration and screen-printing , 2010 .

[14]  Jong Hak Lee,et al.  A New Method of Carbon‐Nanotube Patterning Using Reduction Potentials , 2009 .

[15]  W. Milne,et al.  Field emission characteristics of contact printed graphene fins. , 2014, Small.

[16]  Y. Saito,et al.  Field emission from carbon nanotubes and its application to electron sources , 2000 .

[17]  Akihiro Haga,et al.  A miniature x-ray tube , 2004 .

[18]  Sung Oh Cho,et al.  A vacuum-sealed miniature X-ray tube based on carbon nanotube field emitters , 2012, Nanoscale Research Letters.

[19]  L. Nyborg,et al.  Study of reaction process on Ni/4H–SiC contact , 2006 .

[20]  Yoon-Ho Song,et al.  Highly reliable field electron emitters produced from reproducible damage-free carbon nanotube composite pastes with optimal inorganic fillers , 2014, Nanotechnology.

[21]  H. Dai,et al.  Nanotubes as nanoprobes in scanning probe microscopy , 1996, Nature.

[22]  P. Ajayan,et al.  Three-dimensional metal-graphene-nanotube multifunctional hybrid materials. , 2013, ACS nano.

[23]  Yoon-Ho Song,et al.  A digital miniature x-ray tube with a high-density triode carbon nanotube field emitter , 2013 .

[24]  Yoon-Ho Song,et al.  A vacuum-sealed compact x-ray tube based on focused carbon nanotube field-emission electrons , 2013, Nanotechnology.

[25]  C. Hwang,et al.  Efficient electron emissions from printed carbon nanotubes by surface treatments , 2004 .

[26]  W. D. de Heer,et al.  A Carbon Nanotube Field-Emission Electron Source , 1995, Science.

[27]  G. V. Torgashov,et al.  Electron field emission from nanofilament carbon films , 1995 .

[28]  Hongjie Dai,et al.  Carbon nanotubes: opportunities and challenges , 2002 .

[29]  Jie Tang,et al.  Secondary electron emission in a triode carbon nanotube field emission display and its influence on the image quality , 2012 .

[30]  Jin-Woo Jeong,et al.  Analysis of Failure in Miniature X‐ray Tubes with Gated Carbon Nanotube Field Emitters , 2013 .

[31]  Y. Nakayama,et al.  Adhesive Behavior of Single Carbon Nanotubes , 2010 .

[32]  K. Jiang,et al.  Tip cooling effect and failure mechanism of field-emitting carbon nanotubes. , 2006, Nano letters.

[33]  Y. Shingaya,et al.  Carbon nanotube tip for scanning tunneling microscopy , 2002 .

[34]  N. J. Druten,et al.  Field emission from individual multiwalled carbon nanotubes prepared in an electron microscope. , 2003 .

[35]  D. Chung,et al.  Building a backlight unit with lateral gate structure based on carbon nanotube field emitters , 2009, Nanotechnology.

[36]  Achieving uniform field emission from carbon nanotube composite cold cathode with different carbon nanotube contents: effects of conductance and plasma treatment. , 2009, Ultramicroscopy.

[37]  G. Amaratunga,et al.  Aligned carbon nanotubes/fibers for applications in vacuum microwave amplifiers , 2006 .

[38]  Yuan Cheng,et al.  Fabrication and electron field emission properties of carbon nanotube films by electrophoretic deposition , 2001 .

[39]  J. Warner,et al.  Highly Electron Transparent Graphene for Field Emission Triode Gates , 2014 .

[40]  A. Naoumidis,et al.  Interfacial reaction and adhesion between SiC and thin sputtered cobalt films , 1995 .

[41]  Dejun Li,et al.  Catalyst-free, self-assembly, and controllable synthesis of graphene flake-carbon nanotube composites for high-performance field emission , 2014 .

[42]  V. A. Romanko,et al.  Low-power X-ray tubes (the current state) , 2013 .

[43]  Pierre Legagneux,et al.  Achieving high-current carbon nanotube emitters. , 2005, Nano letters.

[44]  Yusuke Sakai,et al.  Super-miniature x-ray tube , 2004 .

[45]  Y. C. Kim,et al.  Vertical alignment of printed carbon nanotubes by multiple field emission cycles , 2004 .

[46]  Y. Yap,et al.  Effect of graphitic order on field emission stability of carbon nanotubes , 2007, Nanotechnology.

[47]  László Forró,et al.  Field emission properties of multiwalled carbon nanotubes , 1998 .