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InAs/InAsSb type-II strained-layer superlattices for mid-infrared LEDs

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Article number075103
<mark>Journal publication date</mark>30/01/2018
<mark>Journal</mark>Journal of Physics D: Applied Physics
Issue number7
Number of pages9
Publication StatusPublished
Early online date9/01/18
<mark>Original language</mark>English


InAs/InAsSb type-II strained-layer superlattice (SLS) and multiple quantum well (MQW) structures have been studied for their suitability in the active region of mid-infrared LEDs operating at room temperature. A series of InAs/InAs&lt;sub&gt;1-x&lt;/sub&gt;Sb&lt;sub&gt;x&lt;/sub&gt; superlattices with low antimony content (x = 3.8 - 13.5 %) were grown by MBE on InAs substrates and characterised using x-ray diffraction (XRD) and photoluminescence (PL). The SLS show superior temperature quenching behaviour compared with the MQW at the same wavelength, making them more attractive for use in the emitter active region. The 4 K PL spectra of these samples also exhibit the expected peak shift to longer wavelength and a reduction in intensity as the Sb content is increased. Band structure simulations highlight the effects of changing the superlattice, specifically the antimony content and the layer thicknesses, to tailor the overlap of the electron and hole wavefunctions and maximise the radiative recombination rate. Analysis of the temperature dependence of the PL emission spectra enabled the extraction of the quenching energies consistent with some suppression of Auger recombination in both the MQW and SLS structures. The MQW samples exhibit a changeover in the dominant radiative recombination above ~ 100 K associated with thermal emission of holes into the InAs barriers. This behaviour was not observed in the SLS. The resulting strained superlattices on InAs have potential for use as the active region in room temperature mid-infrared LEDs.