1.6 μm Emission from In As Quantum Dots grown on a GaAs Substrate using an AlGaAsSb Metamorphic Buffer

摘要

We report 1.6 μm emission from In As QDs (QDs) grown on a GaAs substrate. The ensemble is grown on a graded digital alloy (DA), which increases the matrix lattice constant from 5.65 A to 5.77 A. The reduced lattice mismatch between the InAs and matrix material produces larger QDs and thereby allows longer wavelength emission compared to standard growth techniques. The resulting QD density ranges from 2xl0~(10) to 8xl0~(10)/cm~2 with QD dimensions of 5nm x 30nm measured using atomic force microscopy (AFM). According to x-ray diffraction (XRD) data and transmission electron microscopy (TEM), the metamorphic buffer is unstrained with low defect density.