Synthesis and characterization of charge carrier diffusion induced nanowire light emitting diodes.

One of humanities grand challenges today is energy, with an ever-increasing energy consumption because of human development, currently driven mainly by China, Brazil, India (and Russia).

Efficient light emitting diode allows reducing energy consumption as illumination consumes approximately 20% of the developed world’s electric power.

LEDs are made from semiconductor materials which have a relatively large refractive index (>3) as compared to the surroundings (~1) that lead to strong reflection and limited emission by total internal reflection since the active regions in a traditional LED are embedded in layers of higher band gap sandwiched between electrical contacts.

In this project we will further develop charge carrier diffusion induced nanowire light emitting diodes. A novel LED architecture concept that we recently demonstrated that the predicted physics worked for. Light emitted from thin NWs does not face the problem of total internal reflection.

To this end, we will optimize synthesis of doped high band gap nanowire pn junctions and grow low band gap thin nanowires on the nanowire side facets. Carriers electrically driven over the pn junction will then diffuse into the lower band gap branches and recombine. This new design offers highly efficient, sustainable light emitting diodes.

Nanowire synthesis, material composition and doping, as well as catalytic particle deposition and is at the heart of the project.