GaSb quantum-well-based “buffer-free” vertical light emitting diode monolithically embedded within a GaAs cavity incorporating interfacial misfit arrays

The authors demonstrate a monolithic, electrically injected, vertically emitting GaSb∕AlGaSb light emitting diode (LED) emitting at 1.6μm comprised of a hybrid GaAs∕GaSb-based structure. The LED is comprised of a GaSb∕AlGaSb quantum well/barrier active region embedded within high index contrast GaAs∕AlGaAs distributed Bragg reflectors (DBRs) using two interfacial misfit (IMF) arrays to relieve the strain induced from the high 8% lattice mismatch between the material systems. The first IMF is formed under compressive strain conditions to enable strain-free, defect-free deposition of GaSb active region directly on the lower GaAs∕AlAs DBRs without need for thick buffer. The second IMF is formed under tensile conditions to enable the upper GaAs∕AlAs DBRs on the GaSb active region. The device demonstrates a maximum output power of 3.5μW. Initial diode optical and electrical characteristics along with IMF band structure are discussed.