Bi-directional dual color mid-IR light emitting diodes

We demonstrate a two-contact, bi-directional, dual color light emitting diode with superlattice active regions operated at wavelengths near 4 μm and 8 μm. The operational wavelength of the device is controlled by the bias polarity. A modification of the long wavelength superlattice facilitated hole transport into the corresponding active region and lead to a more than fourfold increase in output optical power.