Valence-band structure of self-assembled InAs quantum dots studied by capacitance spectroscopy

Abstract

Hole transport into self-assembled InAs quantum dots (QDs) embedded in a GaAs/AlAs matrix was studied by capacitance spectroscopy. From the differential capacitance, a Coulomb blockade energy of EC0h≈22 meV for holes in the ground state was extracted. When the front barrier between the dot layer and the Schottky contact is precisely reduced by selective wet chemical etching, the QD ground state signal shifts to lower gate voltages according to a simple leverage law. From the linear fit of the voltage shift versus the front barrier thickness the hole binding energy of E0h≈194 meV was determined.