Transport spectroscopy of the ultrasmall silicon quantum dot in a single-electron transistor

Abstract

We investigate electron transport through the ultrasmall silicon quantum dot in a single-electron transistor. The device is fabricated in the form of a silicon point-contact channel metal–oxide–semiconductor field-effect transistor. The size of the formed dot is estimated to be as small as 5.3 nm. Negative differential conductance is clearly observed up to 25 K. It turns out that this is caused by discreteness of quantum levels in the silicon dot and variation of the tunneling rates to each level. The fine structure of conductance persists up to 77 K. Modeling of the electron transport through the silicon dot is carried out. Good agreement between experiment and calculation is obtained, which confirms the validity of our model.