Nanoparticles and nanogaps: controlled positioning and fabrication

We present a novel method for fabrication of contacts to nanosize particles. The method is based on conventional optical lithography of GaAs/AlGaAs molecular beam epitaxy grown structures. Taking advantage of the difference in etch rate between GaAs and AlGaAs a narrow gap is formed between metal contacts deposited on the side of a mesa structure. We demonstrate electrostatic trapping of charged metal clusters into these structures using alternating electric fields.