Room temperature InPSb/InAs and InPSb/InAs/InAsSb mid-infrared emitting diodes grown by MOVPE

Strained InAsSb heterostructures are important materials for a variety of new III-V based mid-infrared emitters. In the study InP_0.69-Sb_0.31-InAs light-emitting diodes (LEDs) employing an InAs-InAs_0.94Sb_0.06 multiquantum-well (MQW) active region have been investigated. They were characterised using electro-optical techniques and X-ray diffractometry. The authors have measured the temperature dependence of electroluminescence (EL): at low temperatures, the EL-intensity of the MQW diodes is higher than that of a simple PIN InPSb-InAs-InPSb structure. For both devices, room temperature EL could be resolved (emission wavelength of 3.3 μm, FWHM of 70 meV) which is related to InAs near-bandgap transitions. InAsP/InAsSb MQWs were grown to achieve higher antimony contents in the wells. The heterostructures were strain-balanced and enabled an antimony incorporation of 24% with, at the same time, high structural quality. In the photoluminescence (PL) spectra of InAs_0.95P_0.05-InAs_0.86Sb_0.14 MQWs strong features were observed around 4.2 μm due to atmospheric CO₂ absorption