OPTOELECTRONIC DEVICES HAVING A DIRECT-BAND-GAP BASE AND AN INDIRECT-BAND-GAP EMITTER

摘要

Optoelectronic devices, junctions and methods of fabricating a device or junction where the emitter layer is of an indirect-band-gap material and the base layer is of a direct-band-gap material. The device or junction may have, among other structures and layers, a base layer of a first semiconductor material having a first conductivity type and further having a direct band gap and an emitter layer forming a junction with the base layer. In this embodiment, the emitter layer may be of a second semiconductor material having a second conductivity type and further having an indirect band gap. The optoelectronic device may have the semiconductor material of the emitter layer substantially lattice mismatched with the semiconductor material of the base layer in bulk form. Alternatively, the emitter layer may be substantially lattice matched with the base layer.