Influence of the Epitaxial Growth Conditions of the Active Region on the Performance of Far‐Ultraviolet‐C Light‐Emitting Diodes

Far‐ultraviolet‐C (far‐UVC) light‐emitting diodes (LEDs) emitting at emission wavelengths of 226 or 233 nm with active regions epitaxially grown under different conditions are compared regarding their emission power, operation voltage, and lifetime. A variation in the V/III ratio at the same growth rate was found to have no impact on the LED performance. However, a decrease in growth temperature from 1060 to 1020 °C increases the emission power by around 40%. Furthermore, a decrease in growth rate from 0.080 to 0.014 nm/s increases the emission power by about 50%. At the same time, the L70 lifetime increases by a factor of 3.4. A reduction of the Si doping concentration in the inner quantum well barriers from 4 × 10 18 to 2 × 10 18 cm −3 increases the emission power by more than 40% without affecting the lifetime of the far‐UVC LEDs. Finally, based on these optimizations, 226 nm LEDs with an L70 lifetime above 250 h and an initial emission power of more than 0.4 mW were realized.