LATERAL ELECTRON CONFINEMENT IN NARROW DEEP ETCHED WIRES

Narrow, dry, deep-etched GaAs/GaAlAs quantum wires with modulation dop ing are investigated by electronic Raman scattering (RS) and far-infra red magnetotransmission (FIR). Laterally-confined plasmon and magnetop lasmon dispersions and intensities lead to the determination of the co nfinement potential and the free and trapped electron densities, Free electrons are observed down to a critical width w(c), significantly sm aller under strong illumination (RS, w(c) = 50 nm) than in dark condit ions (FIR, w(c) = 30 nm). The induced changes of the external confinin g potential and lateral electron distribution are analyzed in terms of a semiclassical electrostatic approach. (C) 1998 American Institute o f Physics.