On the role of space-charge scattering in epitaxial GaAs

Abstract

Electron mobility was measured in liquid phase epitaxial GaAs of moderate purity. The relevant charge carrier scattering mechanisms were investigated. It is found that the measured mobility can only be interpreted taking into account scattering on space‐charge regions besides lattice and impurity scattering. The implications of space‐charge scattering are discussed and it is suggested that this scattering mechanism is an almost universally occurring phenomenon in GaAs and presumably in other compound semiconductors, too.

Hole mobility in InP and GaSb

“…Besides lattice scattering (with n i = -1.5 and μ L (300) = 900 cm 2 /Vs for GaSb [4,6,7], and n i = -2.2 and μ L (300) = 150 cm 2 /Vs for InP [6,8] deduced from empirical data from the literature) and ionized impurity scattering (n i =3/2), the inclusion of an additional scattering mechanism characterized with n i = -1/2 was found necessary for the fits. This latter scattering mechanism Is usually ascribed to carrier scattering on space charge regions [9,10], but other physical mechanism could also play a role. The strength of the ionized impurity scattering necessary to account for the low temperature mobility was much less than implied by the acceptor and donor concentrations deduced from the Hall fits.…”

“…space charge scattering [9,10] and dipole scattering [11,12], could possibly account for the μ ∼T -1/2 mobility term. Both express in a certain respect the limitations of the standard single scattering event ionized impurity scattering model.…”