Lasers with δ InAs layers in GaAs

Electroluminescence of lasers with different numbers (1, 3, 5, 7) of δ InAs layers in GaAs prepared by Low Pressure Metal–Organic Vapor Phase Epitaxy was investigated in a broad temperature range from 10 to 400 K. The dependence of the electroluminescence spectra on the number of δ InAs layers and on the separation of these δ InAs layers was studied under pulse excitation in a wide range of current densities. Results show that by increasing the number of δ InAs layers and decreasing the distance between these layers it is possible to decrease the lasing emission energy below 1.15 eV. Our δ InAs lasers operate even at temperatures above 100 °C, they exhibit weak temperature dependence of threshold current density with values lower than 0.2 kA cm−2 and their differential quantum efficiency lies between 12 and 18%.