A Narrow Photoluminescence Linewidth of 19.2 meV at 1.35μm from In_(0.5)Ga_(0.5)As/GaAs Quantum Island Structure Grown by Molecular Beam Epitaxy

Self-organized In_(0.5)Ga_(0.5) As/GaAs quantum island structure emitting at 1.35μm at room temperature has been successfully fabricated by molecular beam epitaxy via cycled(InAs)1/(GaAs)1 monolayer deposition method.Photoluminescence measurement shows that a very narrow linewidth of 19.2 meV at 300 K has been reached for the first time,indicating effective suppression of inhomogeneous broadening of optical emission from the In_(0.5)Ga_(0.5) As island structure due to indium segregation reduction by introducing an AlAs layer and the strain reduction by inserting an In0.2Ga0.8As layer overgrown on the top of islands.The mounds-like morphology of the islands elongated along the[1ī0]azimuth are observed by the atomic force microscopy measurement,which reveals the fact that strain in the islands is partially relaxed along the[1ī0]direction.Our results present important information for the fabrication of 1.3μm wavelength quantum dot devices.