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

Abstract

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 1−x Sb x superlattices with low antimony content (x = 3.8-13.5%) were grown by MBE on InAs substrates and characterised using x-ray diffraction and photoluminescence (PL). The 4 K PL spectra of these samples 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 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 quenching energies that demonstrate some suppression of Auger recombination in both the MQW and SLS structures. The MQW samples exhibit a changeover in the dominant radiative recombination process above ~100 K associated with thermal emission of holes into the InAs barriers; this behaviour was not observed in the SLS samples. These SLS structures have the potential for use as the active region in room temperature mid-infrared LEDs.

Heteroepitaxial Integration of Mid-Infrared InAsSb Light Emitting Diodes on Silicon

“…where m e * and m hh * are the conduction and valence band carrier effective masses and E g is the bandgap energy [25]. Using linear interpolation for the carrier effective masses, the activation energy was calculated as E CHCC = 22 meV.…”

Locally‐Strain‐Induced Heavy‐Hole‐Band Splitting Observed in Mobility Spectrum of p‐Type InAs Grown on GaAs

“…[41]), which can be observed in the strained 200 nm‐thick interlayer, as in our case. Such splitting is sometimes intentionally used to suppress the Auger phenomenon in strained‐layer superlattices . This effect makes that the light‐hole band moves down in the energy scale, away from the Fermi level.…”

“…Such splitting is sometimes intentionally used to suppress the Auger phenomenon in strained-layer superlattices. [42] This effect makes that the light-hole band moves down in the energy scale, away from the Fermi level. Therefore, we cannot observe light holes from that interlayer and for the same reason we cannot observe electrons from the bulk part of the InAs layer.…”

Advanced mid-infrared lightsources above and beyond lasers and their analytical utility

“…Around the same time, Keen et al [ 83 ] compared InAs/InAs 1-x Sb x superlattices and MQW structures LEDs for a Sb fraction of x = 3.8–13.5% at room temperature. They were able to show that both the 4 K photoluminescence spectra of the superlattice samples and the MQW samples showed peak shifts to longer wavelengths and a decrease in intensity as the antimony content was increased.…”