PARALLEL CASCADE QUANTUM WELL LIGHT EMITTING DEVICE

摘要

The present invention relates to quantum well semiconductor light emitting devices and other devices that utilize type-II quantum wells and interband transitions of energy states between conduction and valence bands for light emission, resulting in improved radiative efficiency. The semiconductor light emitting devices comprise a multilayer semiconductor structure comprising a plurality of active regions (12), each active region being separated from its adjoining active regions by an injection region (14) that serves as the collector for the preceding active region and the emitter for the following active region. Each active regions comprises multiple quantum well regions or finite superlattice regions to improve carrier injection efficiency and enhance optical gain. Type-II tunnel junction are utilized in the injection regions such that carriers can be reused through a spatial interband coupling after an interband transition for photon emission, leading to the realization of interband cascade configuration under an appropriate bias.