Enhanced performance of bipolar cascade light-emitting diodes by doping the aluminum oxide apertures

Performance improvements in multiple-stage, single-cavity bipolar cascade light-emitting diodes including reduced operating voltages, enhanced light generation, and reduced device heating are obtained by doping intracavity aluminum oxide apertures with silicon. This doping results in a reduced electron energy barrier and, therefore, a reduced series resistance which leads to better power and heating characteristics. Nearly 50% reductions in operating voltages, 200% increases in light power, and increased operating range are demonstrated. We discuss the direct implications of these results for the design of bipolar cascade vertical-cavity surface-emitting lasers.