InAs(Sb)/InP(100) quantum dots for mid-infrared emitters: observation of 2.35 mum photoluminescence

Theoretical and experimental studies of the electronic properties of InAs(Sb) quantum dots (QDs) grown on InP substrate are presented. Unstrained bulk InAsSb present direct gap between 0.1 eV to 0.35 eV suitable for mid infrared emitters (2-5 mum ). However, strain and quantum confinement effects may limit the extension of the emission spectrum of these nanostructures towards the longer wavelengths. Various combinations of barrier materials are considered in the simulations. Photoluminescence (PL) spectroscopy experiments on molecular beam epitaxy (MBE) grown samples show promising results. We obtained PL peak beyond 2 mum at room temperature (RT) with InAs/InGaAsP/InP(100) QDs. High arsine flow rate during the growth of the QDs makes possible this long emission wavelength. Two ways are investigated to incorporate antimony in InAs/InGaAs/InP(100) nanostructures: growth interrupt of InAs QDs under Sb flux and direct growth of InAs(Sb). A red-shift of the PL peak from 1.85 mum to 2 mum is observed in the first case whereas emission wavelengths as long as 2.35 mum are observed in second case.