Size Control and Photoluminescence Characteristics of InSb Quantum Dots on GaSb Substrates Grown by Molecular Beam Epitaxy

Abstract

InSb self‐assembled quantum dots (QDs) have the possibility to increase the luminescence intensity of light‐emitting diodes operating in the midinfrared region. As a first step toward the midinfrared luminescence, the single‐layer InSb QDs are grown on GaSb (100) substrates by molecular beam epitaxy and the effects of V/III ratio and InSb coverage on size and density of InSb QDs and photoluminescence (PL) characteristics are investigated. As the V/III ratio increases, the distribution of QD height broadens and goes from monomodal to multimodal. The increase in the number of large QDs and their multimodal distribution are thought to be due to the ripening process. The PL intensity is maximum at a V/III ratio of 2 with PL wavelength of 1.76 μm. As the InSb coverage increases at a V/III ratio of 2, QD size and density increase while maintaining a monomodal distribution in QD size. However, the PL peak intensity decreases with increasing InSb coverage due to the increase of nonradiative QDs. The highest PL peak intensity at an InSb coverage of 2.0 monolayer and a V/III ratio of 2 with PL wavelength of 1.69 μm are obtained. The present single‐layer InSb QD shows the emission in the near‐infrared region.