Enhanced field emission from LaB6 thin films with nanoprotrusions grown by pulsed laser deposition on Zr foil

• Published in: Applied surface science 2008-03, Vol.254 (11), p.3601-3605
• Main Authors: LATE, Dattatray J, DATE, Kalyani S, MORE, Mahendra A, MISRA, Pankaj, SINGH, B. N, KUKREJA, Lalit M, DHARMADHIKARI, C. V, JOAG, Dilip S
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Field emission, ionization, evaporation, and desorption; Laser deposition; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.11.015

Lanthanum hexaboride (LaB6) films have been deposited on a zirconium foil by pulsed laser deposition method. The field emission studies of the LaB6 deposited film have been performed in the planar diode configuration under ultra high vacuum conditions. The Fowler-Nordheim plots were found to be linear in accordance with the quantum mechanical tunneling phenomenon. A typical field emission current of 7.02muA was drawn at an applied electric field of 2V/mum. The field enhancement factor is calculated to be 8913cm-1, indicating that the field emission is from nanoscale protrusions present on the emitter surface. The atomic force microscope (AFM) investigation of the surface clearly shows the conical shaped nanoprotrusions of few hundred nanometers with asperities of 20-40nm on its top. The emission current-time plot recorded at the pre-set value of emission current of 5muA over a period of more than 3h exhibits an initial increase and subsequent stabilization of the current. The results reveal that the LaB6/Zr field emitter obtained by the pulsed laser deposition (PLD) is a promising cathode material for practical applications in field emission-based devices.