Observation of single electron effects using HEMT

Abstract

We have fabricated laterally confined quantum dots and high electron mobility transistors (HEMTs) monolithically. The HEMT gate is capacitively coupled to the quantum dot. The drain current of the HEMT is sensitive to the voltage variations caused by single electron charging in the dot. We have observed a wide variety of HEMT current oscillations which correlate with Coulomb Blockade oscillations. The amplitude of HEMT current strongly depends on the bias conditions of the tunneling barriers. In certain bias conditions, the HEMT becomes insensitive to the electron charging in the dot even though Coulomb Blockade conditions are satisfied. This property can be explained qualitatively by using a simple model.