Tunnel injection GaN/AlN quantum dot UV LED

Light weight and robust ultraviolet (UV) light emitting sources find multitude of uses, for example in water purification, sterilization, bio sensors, solid state lighting and lithography. Direct bandgap III-Nitride semiconductors exhibit bandgap energies extending upto 6.2 eV (210 nm, deep UV). Thus, III-Nitrides are potential candidates for fabricating UV LEDs. But as we move to higher Al compositions to reach shorter wavelengths the internal quantum efficiency (IQE) severely degrades due to factors such as the valence band asymmetry, high threading dislocation densities, quantum confined Stark effect and inefficient n- and p-type doping. To mitigate the adverse effects of such factors and boost the IQE, we propose and demonstrate a new design which incorporates GaN quantum dots (QDs) in AlN barriers and uses tunneling to inject and transfer carriers through the active region.