Development of novel UV LED technology using cathodoluminescence inspection
Light emitting diodes (LEDs) have developed into a mature and widely used technology over the last decades, finding applications in displays, ambient/car lighting, remote controls, optical switches and more. The active light emitting layer in LEDs is usually composed of compound III/V direct bandgap semiconductors such as (In)GaN for blue/visible LEDs and GaAs/InP for IR LEDs. Such devices can be made with high external quantum efficiencies (EQE > 70%) and good stability (over 30000 hrs operating time) while maintaining a low price point. The advancement of LED technology has effectively rendered older techniques such as tungsten filament light sources almost obsolete. More recently, there has been significant interest in pushing LED technology beyond the IR and visible spectral range into the ultraviolet.