Photoconductivity Resonance Tunneling Spectroscopy of the Electron States in the InAs/GaAs Quantum Dot Heterostructures

Abstract

The electric-field behavior of the resonance features in the photoelectric characteristics of InAs/GaAs heterostructures is studied. We discuss the emission mechanism of the charge carriers excited from InAs quantum dots into the GaAs matrix. It was shown that at the temperature of liquid nitrogen the photocurrent in a strong transverse electric field is only determined by the effect of electron tunneling through the barrier formed at the quantum-dot interfaces. Comparison of the experimental curves with the quasi-classical expression for the tunneling current component and analysis of the potential structure allowed us to specify some parameters of investigated heterostructures. Analysis of the electric-field dependences of the photocurrent-tunneling component revealed resonance peculiarities connected with the local defect states in the vicinity of InAs/GaAs interface.