The efficiency of UV LEDs based on GaN/AlGaN heterostructures

Abstract

The UV LED heterostructures have been obtained by HVPE approach and investigated by XRD, AFM and PL methods. The experiment shows that the peak wavelength of UV LEDs is in the range of 360-365 nm with FWHM of 10-13 nm. At operating current of 20 rnA the active region temperature Tj is 43°C, the output optical power and efficiency -1.14 mW and 1.46 %, respectively. It is presented a model based on corpuscular Monte Carlo method in order to calculate the light extraction index. The simulation results allow us to propose the ways to increase the efficiency of UV LEDs by 3-4 times: surface interfaces texturing, optimization of the design of heterostructures, and the use of lenses.

Physical and technological analysis of the AlGaN-based UVC-LED: an extended discussion focused on cubic phase as an alternative for surface disinfection.

“…On the other hand, the hexagonal phase of AlGaN presents the advantage over the cubic phase of requiring a lower concentration of Al to reach higher E g ; nonetheless, when working with h-AlGaN, it is very important to consider that built-in internal electric fields cause a large shift to lessenergetic emission [80], as will be discussed in the next sections. In general, due to the fact that the hexagonal structure is the stable phase of III-nitrides, the state of art unfolds studies that support sapphire as the main substrate in UVC LED growth [74,[81][82][83][84][85][86][87].…”

A Review of Light-Emitting Diodes and Ultraviolet Light-Emitting Diodes and Their Applications

“…Junction [33] • Zinc oxide (ZnO) homojunction [34] • Aluminum gallium nitride (AlGaN) heterojunction [35] • DH junction [32] • MQW Junction [33] • ZnSe homojunction [36] • InGaN heterojunction…”