Ron Kroon

Secondary electron emission measurements on synthetic diamond films

Abstract During the electron irradiation of synthetic diamond films, three successive regimes are encountered as a function of the electron dose: (1) a reduction of the downward band bending of energy levels at the sample surface because an excess of secondary electrons leaves the sample; (2) the creation of an internal electric field in which secondary electrons drift to the surface, leading to an appreciable increase in the secondary emission and to a linear relation between the primary electron energy and the secondary electron yield; and (3) the desorption of hydrogen terminating the carbon surface bonds. The secondary emission thus decreases to very low values. The rate of decrease of secondary emission is similar for C:H- and C:H:Ba-terminated diamond surfaces.

Influence of oxygen on the thermal desorption of Cs from Si(100)

This paper describes the thermal desorption of Cs from oxidized Si(100), measured as a function of sample temperature and oxygen coverage. The desorption process is found to be governed by a broad distribution of the activation energy for thermal desorption of the Cs atoms, which reflects the considerable inhomogeneity of the Si surfaces. The weight of the distribution is found to shift to higher activation energy with increasing oxygen coverage of the Si substrates.