Molecular beam epitaxial growth of InSb sub-monolayer insertions in an InAs matrix, exhibiting intense mid-IR photoluminescence (PL) up to room temperature, is reported. The InSb insertions are fabricated by an exposure of the InAs surface to an antimony Sb-4 flux. The nominal thickness of the insertions grown at different temperatures (400-485 ° C) changes in the 0.6-1 monolayer range, resulting in the emission wavelength variation from 3.9 to 4.3 μ m at 300 K. An integral PL intensity drop from 80 to 300 K does not exceed 20 times. The laser emission at a wavelength of 3.08 μ m (T = 60 K) with the threshold current density of 3-4 kA/cm(2) under pulse injection pumping has been demonstrated in a hybrid p-AlGaAsSb/InAs/n-CdMgSe double heterostructure with the multiple type II InSb/InAs nanostructures in the active region. © 2005 Elsevier B.V. All rights reserved.