Dual-Color InAs/GaSb Cascaded Superlattice Light-Emitting Diodes

Over the last decade, InAs/GaSb superlattice structures have become an increasingly important technology for infrared applications. By stacking two superlattice structures back-to-back with a conductive layer separating them, independently operable, dual color, cascaded InAs/GaSb superlattice light-emitting diodes were grown via molecular beam epitaxy on (100) GaSb substrates. An 8 x 8 matrix of 48-mu m pitch pixels was fabricated using standard photolithography and wet-etch techniques. At 77 K, the emitted wavelengths are in the 3.2-4.2- and 4.2-5.2-mu m range, with peak wavelengths at 3.81 and 4.72 mu m. In quasi-continuous operation, radiances in excess of 2 W/cm(2) . sr from the longer wave and 5 W/cm(2) . sr from the shorter wave emitters are achieved.