Fabrication and characterization of metal-semiconductor field-effect-transistor-type quantum devices

The fabrication and low-temperature characterization of quantum devices using a metal-semiconductor field-effect-transistor-(MESFET) type wafer was carried out. It was observed that the measured transport data of both devices at 4.2 K showed single-electron tunneling (SET) behavior with strong modulation of Coulomb blockade in a wide gate-bias range. It was shown that approximately 10% of the dopant atoms were ionized at 4.2 K, and the size of unintentional quantum dots (QD) estimated from the transport data was consistent with the average distance between ionized donors. It was found that the nanodevices also showed quantum mechanical effects such as SET through excited states and negative differential resistance (NDR).