Secondary Electron Emission from Non-NEA GaAs

Following sub-keV electron bombardment of GaAs <100> crystals, laser-

light-induced effects in the kinetic secondary electron yield (SEY) have been

observed for p-type, n-type, and undoped samples. The SEY is measured

with super- and sub-bandgap lasers of wavelengths 812 nm and 980 nm,

respectively, coincident with the electron beam. The effects on the SEY

have been observed to vary with dopant type and laser illumination. Light-

induced effects on the secondary electron energy distribution have also been

measured. While the SEY has been measured for GaAs at higher energies (≥

1 keV) with negative electron affinity (NEA) surfaces, there are no current

studies of SEY at relatively low energies with non-NEA GaAs surfaces; with

or without laser excitation of the solid. [1,2] The work presented here is

aimed towards the development of novel sources of polarized electrons as

well as the development of new methods of time-resolved measurements of

electron emission.

[1] R. U. Martinelli et al. J. Appl. Phys., 43, 4803–4804, (2003)

[2] W. A. Gutierrez et al. Appl. Phys. Lett., 21, 249–250, (2003)