A feature story on Semiconductor Today
14 July 2023
Improving micron-scale AlGaInP red LED performance
University of California Santa Barbara (UCSB) in the USA and Seoul Viosys Co Ltd of South Korea have used a combination of thermal annealing, chemical treatment, and passivation, to reduce performance degradation in micron-scale aluminium gallium indium phosphide (AlGaInP) red light-emitting diodes (LEDs) [Applied Physics Express, v16, p066503, 2023]
The researchers report: “The devices with sidewall treatments demonstrated a reduction in external quantum efficiency (EQE) of 20%, corresponding to the lowest efficiency drop due to the size effect in AlGaInP μLEDs to date.”
Micron-scale LEDs are being developed for display applications. Although nitride-based InGaN LEDs are used to cover the green and blue parts of the visible color range, InGaN red LEDs suffer from much reduced efficiency and low light output powers. Normal red LEDs use other material systems such as AlGaInP.