Highest Density 1.3 µm InAs Quantum Dots Covered with Gradient Composition InGaAs Strain Reduced Layer Grown with an As2 Source Using Molecular Beam Epitaxy

Abstract

We propose a GaAs-based 1.3 µm InAs quantum dot (QD) structure for optical devices that uses dimeric arsenic (As2) and a highly strained GaInAs cover layer. The characteristics of 1.3 µm InAs QDs that employ As2 are different from those of QDs that use As4. Our optimum structure exhibits the first room temperature emission of over 1.3 µm with a linewidth of 22 meV and a high density of over 1 ×1011 cm-2 using only a cover layer. We were also able to achieve a very high density of 3.3 ×1011 cm-2 and a full width at half mazimum of 23 meV for a triple-stack structure within the critical thickness. This result is promising as regards achieving an optical device with QDs of over 1.3 µm on a GaAs substrate for use in fiber communications.