A Narrow Photoluminescence Linewidth of 19.2 meV at 1.35μm from In_0.5Ga_0.5As/GaAs Quantum Island Structure Grown by Molecular Beam Epitaxy

Self-organized In_0.5Ga_0.5As/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_0.5Ga_0.5As island structure due to indium segregation reduction by introducing an AlAs layer and the strain reduction by inserting an In_0.2Ga_0.8As 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.