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We have fabricated through-hole-type nano-contacts by using both photolithography and electronbeam lithography (EBL) followed by reactive ion etching (RIE). The resistance of the Cu-Cu contact reveals that our nano-constrictions are in the range from the ballistic region to the diffusive region of transport, which is determined by the diameter of the through-hole with respect to the Fermi wavelength of Cu. The clean Cu-Cu contact shows longitudinal (LA) and transverse acoustic (TA) Cu phonon peaks in the energy spectrum near the ballistic region. The transport spectrum of the resistance in the diffusive region is dominated by the background effect, which flattens the features of the phonon peaks by secondary processes such as scattering and re-absorption.??