N -type anode layer, high-power MWIR superlattice LED

Abstract

Cascaded superlattice LEDs were designed, grown, fabricated, and tested with an n-type anode structure consisting of a variably doped n-GaSb buffer layer and a variable tunnel junction of n-GaxIn1-xAsySb1-y/p-GaSb in place of a conventional p-doped anode contact layer. The elimination of p-doped contact layers from the structure was found to reduce parasitic optical absorption and ohmic loss. After selecting the ideal design from the 4 stage test structures, a nominally identical 16 stage n-type anode structure was grown, yielding an MWIR radiance of 6.7 W/cm2/sr.