Fabrication of Al nanoparticles and their electrical properties studied by capacitance–voltage measurements

Nanometer-scale Al particles are fabricated and are embedded in a GaAs matrix using molecular beam epitaxial technique. The Al particle is self-assembled on GaAs by supplying an Al molecular beam. The average particle size is found to be 25 nm. The density is 7 1010 cm 2 when Al of 6.2 1015 atoms/cm2 is supplied on (1 0 0)GaAs at a substrate temperature of 300 8C. Clear hysteresis and plateaus in capacitance–voltage (C– V) curves are found in an Al-embedded sample, whereas monotonic increase of capacitance is obtained in a reference sample having an AlAs layer instead of Al. This difference results from trapping of electrons by the Al particles, suggesting that the particles have metallic character