RANDOMLY DISTRIBUTED ULTRASMALL METAL PARTICLES ON THE SURFACE OF HIGH-MOBILITY 2DEG SAMPLES

Uniformly sized ultrasmall silver particles, 33 nm in diameter, have been deposited on the surface of modulation-doped GaAs/Al0.33Ga0.67As samples, containing a high mobility two-dimensional electron gas (2DEG). The particles are distributed randomly on the surface. It can be expected, that the carrier concentration underneath each particle is influenced by the change in the surface condition, if the 2DEG is sufficiently close to the surface. Since the size of the particles is of the order of the electron wavelength, this technique is potentially interesting for the study of quantum size effects. We report on the first experimental results from magnetotransport experiments. No indication of electron-wave interference effects was found. However, in some of the samples, we observe an increase of the mobility when a few percent of the surface is covered with aerosol particles. This phenomenon is described and discussed.