Electric-Field Switching of Bright and Dark Excitons in Semiconductor Crossed Nanowires

We investigate theoretically the exciton states in semiconductor crossed nanowires (CNWs) and it is found that the energy spectrum and electro-PL spectrum of the exciton in the CNWs can be tuned by the size of the nanowires using electric fields. An interesting bright-to-dark exciton transition can be found and it significantly affects the photoluminescence spectrum by the electric fields, which can be used to design new types of optoelectronic devices.