Tuning the energy spectrum of InAs/GaAs quantum dots by varying the thickness and composition of the thin double GaAs/InGaAs cladding layer

Abstract

It is shown that the ground state transition energy in quantum dots in heterostructures grown by atmospheric-pressure MOCVD can be tuned in the range covering both transparence windows of the optical fiber at wavelengths of 1.3 and 1.55 µm by varying the thickness and composition of the thin GaAs/InxGa1−xAs double cladding layer. These structures also exhibit a red shift of the ground state transition energy of the InxGa1−xAs quantum well (QW) as a result of the formation of a hybrid QW InxGa1−xAs/InAs (wetting layer) between the quantum dots (QDs). The Schottky diodes based on these structures are characterized by an increased reverse current, which is attributed to thermally activated tunneling of electrons from the metal contact to QD levels.