Une détermination du coefficient d'auto-diffusion de surface avec des pointes à émission de champ (tungstène)

• DOI: 10.1016/0039-6028(74)90138-1
• Publication Date: 2002-10-18T15:23:01Z
• Authors: A. Piquet; H. Roux; Vu Thien Binh; R. Uzan; M. Drechsler
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract To measure the surface self-diffusion coefficient, a method is described which is based on the increase of the curvature radius of a tip (Nichols and Mullins). This radius increase depending on temperature and time is measured under ultra high vacuum condition. The cleanliness of the surface is controlled by field electron microscopy. The radius variation is measured in situ by Fowler-Nordheim characteristics, and the initial and final radius by scanning electron microscopy. Measured are, for tungsten between 2100 and 2850°K, the activation energy ( 3.1 eV atome ) and the diffusivity ( 0.9 cm 2 s ) .