Solid state light sources based on compound semiconductors are opening a new era in general lighting and will contribute significantly to a sustainable energy saving. For a successful and broad penetration of LEDs into the general lighting market two key factors are required: high efficiency and low cost. Two new disruptive technologies based on nano-structured semiconductors are proposed to address these key factors. A novel epitaxial growth technique based on nano-rod coalescence will be explored to realize ultra-low defect density templates which will enable strain-relieved growth of LEDs and thus achieve higher efficiency. The second highly innovative approach is the growth of directly emitting Gallium nitride based nano-rod structures. These structures are expected to produce exceptionally high efficiency devices covering the whole visible spectrum and even phosphor-free white LEDs. Significantly, our new nano-structured compound semiconductor based technology will enable LED growth on low-cost and large-area substrates (e.g., Silicon) as wafer bowing will be eliminated and thus lead to a dramatic reduction in production costs.

The main objectives over the three years are: Profound understanding of the growth mechanisms and properties of nano-rod systems New materials and process technologies (wafer-scale nano-imprinting, dry etching, device processing) for LEDs based on nano-structured templates and nano-rod LEDs.

Demonstrators:
-Phosphor-converted white LEDs based on nano-structured sapphire templates (efficacy 150 lm/W @ 350 mA) and Silicon templates (efficacy 100 lm/W @ 350 mA)
-Blue, green, yellow and red emitting Nano-LEDs (external quantum efficiency 10%)
-Novel phosphor-free white-emitting Nano-LEDs (external quantum efficiency 2%).

Realising the objectives of SMASH will start a new generation of affordable, energy-efficient solid state light sources for the general lighting market and will push the LED lamp and luminary business in Europe.