Abstract
The InAs/AlSb material system is a promising candidate for the development of short wavelength quantum cascade lasers because of the large conduction band offset of 2.1 eV. In this letter, we present a study of room temperature electroluminescence of InAs/AlSb quantum cascade structures as a function of the emission wavelength. Intersubband emission with a transition energy of 500 meV (λ=2.5 μm) has been obtained.