Effect of band structure modification on the output characteristics of AlGaInP light emitting diodes

Summary form only given. Visible light emitting diodes (LEDs) based on the AlGaInP alloy system are very efficient in the 630-590 nm wavelength region compared with conventional light sources. However, at shorter wavelengths the efficiency decreases significantly due to carrier distribution among the direct and indirect conduction band extrema. We have directly determined the effect of carrier transfer to the indirect extrema in the active and cladding layers of AlGaInP LEDs by monitoring the electroluminescence (EL) output emission as a function of the energy separation between the different conduction bands. A quasi-continuous change in the separation between the AlGaInP direct minimum (/spl Gamma/A) and the indirect (X) levels in the active and cladding layers was achieved by varying the Al composition and by using hydrostatic pressure.