Charging Effect of InAs Dots in Split-Gate High Electron Mobility Transistor Structure

We report on a series of distinct current oscillations due to charging of InAs dots in a GaAs double heterojunction field-effect transistor (DHFET) with self-assembled InAs dots formed on the bottom of the channel. These peaks can be interpreted by the tunneling of electrons from the channel to the InAs dots resulting in the threshold voltage shift. Observed number of currrent peaks suggests that each dot can accomodate up to six electrons. Based on the InAs dot size estimated by Transmission Electron Microscope (TEM) observation, relatively large effective mass of 0.06 m0–0.08 m0 were estimated in order to account for accomodation of six electrons per dot.