| Popis: |
Field electron emission of Mo on Mo, W on W and Re on Re vacuum deposits has been investigated. Many monatomic layers of Mo, W and Re have been deposited on the tip of the same material. A wide range of substrate temperature has been used: from room temperature to 660, 800 and 660 K for Mo, W and Re respectively. Three surface forms of deposit have been obtained in these temperature ranges: (1) low-temperature disordered condensate; (2) so called replication; and (3) ordered crystal outgrowths (so called "collars"). Then the stability of field electron current was examined. As a result it was shown that the stage of replication was characterised as the most stable form. The most unstable situation was typical for the low-temperature disordered condensate. |
