| 摘要 |
The present invention relates to quantum well semiconductor light emitting devices such as lasers and other devices that utilize type-II quantum wells and interband transitions of energy states between the conduction band and the valence band for light emission, resulting in significant improvement in radiative efficiency. The semiconductor light emitting devices comprise a multilayer semiconductor structure comprising a plurality of essentially identical active regions, each active region being separated from its adjoining active regions by an injection region that serves as the collector for the preceding active region and the emitter for the following active region. Each of said active regions comprises multiple quantum well regions or finite superlattice regions to improve carrier injection efficiency and enhance optical gain without using a large number of cascade stages. This can reduce the operating voltage and increase the power efficiency. Type-II tunnel junctions 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, which further improves the device performance. |
