THE WORK FUNCTION OF THE CU-DEPOSITED TI EMITTER

We have measured the field-emission characteristics of the Cu-deposite d Ti emitter and studied the change in the work function due to the Cu deposition. The emitter work function was obtained from the slope of the Fowler-Nordheim plot. Upon depositing Cu on Ti, we found that the work function increases by 0.1-0.2 eV. Annealing the deposited emitter gives a larger increase in the work function. We could not observe th e reduction in work function predicted by Yoshitake and Yoshihara [J. Vac. Sci. Technol. A13 (1995) 2407] for the Cu-segregated Ti emitter. This discrepancy indicates the importance of the structural difference between the segregated and metal-deposited surfaces, which has not be en considered in the study of the change in the work function due to s urface segregation. (C) 1998 Elsevier Science B.V. All rights reserved .