Characterization of InAs quantum dots in strained $InxGa1−xAs$ quantum wells

The properties of InAs quantum dots placed in a strained InGaAs quantum well are investigated. The structures are grown by solid-source molecular beam epitaxy on GaAs substrates and are characterized using photoluminescence and atomic force microscopy. Emission wavelength and the optical quality of the quantum dots vary with growth temperature and also depend on the position of the dots in the well. A strong dependence of the dot properties on the capping conditions is established. A postgrowth anneal similar to a typical laser cladding growth results in a large photoluminescence (PL) blueshift and reduces the PL intensity by more than two orders of magnitude. It is shown that these dots-in-a-well structures have superior optical properties as compared to conventional InAs dots in a GaAs matrix, and their emission wavelength can be tuned past the technologically important wavelength of 1.3 μm.