Secondary Electron Emission from Non-NEA GaAs

Laser-light-induced effects in the kinetic secondary electron yield (SEY) are observed for p-type, n-type, and undoped GaAs. A beam of 0.1 - 1 keV electrons incident on the GaAs produces secondary electrons. The SEY is measured for different angles of electron incidence with lasers of wavelength 812 nm and 980 nm incident at the same spot where the electrons strike the GaAs. This light produces super- and sub-bandgap direct excitation respectively. While the SEY has been measured in GaAs for higher energies (> 1 keV) with negative electron affinity (NEA) surfaces, there are no studies of SEY at relatively low energies with non-NEA surfaces that involve 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 developoment of new methods of time-resolved measurements of electron emission.

[1] R. U. Martinelli et al. Journal of Applied Physics, vol. 43, no. 11, pp. 4803–4804, (1972).

[2] W. A. Gutierrez et al. Applied Physics Letters, vol. 21, no. 6, pp. 249–250, (1972).