Numerical study on the optimisation of AlGaN-based deep ultra-violet light emitting diodes single quantum wells

Solid-state ultra-violet light emitting diodes (UV-LEDs) based on aluminium gallium nitride (AlGaN) semiconductors have drawn considerable attention because their energy can be tuned from 3.4 eV (GaN) to 6.2 eV (AlN) by changing Al content. Subsequently, AlGaN-based UV-LEDs with a full wavelength coverage of UV spectral range (400-200 nm) can be fabricated. However, their external quantum efficiency, especially the deep UV-LEDs, is still much lower than commercially available blue LEDs. To improve the efficiency of the AlGaN-based deep UV-LEDs, the effects of the thicknesses, pairings, and Al composition of quantum wells (QWs) are examined using self-consistent simulation software. The normalised simulation results show that the emission wavelength is blue shifted as the Al composition increased in single quantum well (SQW) UV-LEDs. The simulation also assessed the effect of SQWs configuration and discovered that changing the SQWs' thickness leads to considerable variance in device power in a log scale.