Design and demonstration of Al_xIn_1−xP multiple quantum well light-emitting diodes

Direct bandgap Al_xIn_1−xP alloys offer an advantage for red and amber light-emitting diode (LED) operation over conventional (Al_xGa_1−x)_0.5In_0.5P alloys due to their higher direct bandgap energies. However, the coupled variation of its bandgap energy and lattice constant present challenges for fabricating quantum well (QW)-based LED devices on GaAs substrates. Here, we present the design and demonstration of Al_xIn_1−xP red and amber LEDs incorporating multiple QW structures. Strain balancing the QW layers and manipulating the Al_xIn_1−xP conduction band energy through control of spontaneous atomic ordering produce structures with higher energetic barriers to electron leakage compared to (Al_xGa_1−x)_0.5In_0.5P LEDs. We also discuss future improvements that must be made to realize high efficiency red and amber LEDs. (paper)