Field emission studies of pulsed laser deposited LaB6 films on W and Re.

Lanthanum hexaboride films were grown on tungsten and rhenium tips and foils by pulsed laser deposition. The X-ray diffraction spectra of the PLD LaB6 films on both the substrates show crystalline nature with average grain size approximately 125 nm. The field emission studies of pointed and foil specimens were performed in conventional and planar diode configurations, respectively, under ultra-high vacuum condition. An estimated current density of approximately 1.2 x 10(4) A/cm2 was drawn at the electric field of 3 x 10(3) and 6 x 10(3) V/microm from the LaB6 coated tips of tungsten and rhenium, respectively. The Fowler-Nordheim plots were found to be linear showing metallic behavior of the emitters. The field enhancement factors were calculated from the slopes of the Fowler-Nordheim plots, indicating that the field emission is from LaB6 nanoscale protrusions present on emitter surfaces. The emitters were operated for long time current stability (3 h) studies. The post-field emission surface morphology of the emitters showed no significant erosion of LaB6 films during 3 h continuous operation. The observed behavior indicates that it is linked with the growth of LaB6 films on W and Re. These results reveal that the LaB6 films exhibit high resistance to ion bombardment and excellent structural stability and are more promising emitters for practical applications in field emission based devices.

[1]  Z. Guo,et al.  Nano-structured films formed on the AISI 329 stainless steel by Nd-YAG pulsed laser irradiation , 2004 .

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

[3]  D. Late,et al.  Field emission from a-GaN films deposited on Si (100) , 2004 .

[4]  Otto Zhou,et al.  Field Emission of Electrons from Single LaB6 Nanowires , 2006 .

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

[6]  W. Hsu,et al.  Large-scale production of NbS(2) nanowires and their performance in electronic field emission. , 2004, Angewandte Chemie.

[7]  V. Craciun,et al.  Pulsed laser deposition of crystalline LaB6 thin films , 2005 .

[8]  J. M. Kim,et al.  Field-emission characteristics from wide-bandgap material-coated carbon nanotubes , 2002 .

[9]  H. Dai,et al.  Self-oriented regular arrays of carbon nanotubes and their field emission properties , 1999, Science.

[10]  C. Balasubramanian,et al.  Field emission from open ended aluminum nitride nanotubes , 2002 .

[11]  Baojun Li,et al.  The light-emitting properties of Ge nanocrystals grown by pulsed laser deposition , 2005 .

[12]  L. M. Kukreja,et al.  Field emission studies on well adhered pulsed laser deposited LaB6 on W tip , 2006 .

[13]  K. Fukuda,et al.  Field electron emission from LaB6 and TiN emitter arrays fabricated by transfer mold technique , 2002 .

[14]  Imtiaz S. Mulla,et al.  Ultralow threshold field emission from a single multipod structure of ZnO , 2006 .

[15]  R. Fowler,et al.  Electron Emission in Intense Electric Fields , 1928 .

[16]  Y. Lamy,et al.  High brightness electron beam from a multi-walled carbon nanotube , 2002, Nature.

[17]  G. J. McCarthy,et al.  JCPDS-International Centre for Diffraction Data , 1981 .

[18]  R. Flammini,et al.  Surface characterisation of nano-structured carbon films deposited by Nd:YAG pulsed laser deposition , 2005 .

[19]  A. Govindaraj,et al.  Field emission properties of boron and nitrogen doped carbon nanotubes , 2006 .