ZnSe/BeTe Type-II Light Emitting Diodes

Abstract

We report on the growth and characterization of LEDs with wavelengths from 640 to 515 nm based on ZnSe/BeTe type-II transitions. Despite a spatially indirect transition the LEDs show bright luminescence at room temperature probably due to a strong carrier confinement at the interface. In addition, the device lifetime reaches values above 1000 h at 20 A/cm2. This good device stability can be explained by a small number of stacking faults at the GaAs–BeTe interface, the reduction of strain in the active zone, the absence of nitrogen-doped ZnSe, and the fully pseudomorphic p-BeTe contact.