T. Kolbe¹, A. Knauer¹, J. Rass¹, H.K. Cho¹, S. Hagedorn¹, F. Bilchenko², A. Muhin², J. Ruschel¹, M. Kneissl^1,2, S. Einfeldt¹, and M. Weyers¹

Published in:

Appl. Phys. Lett., vol. 122, no. 19, pp. 191101, doi:10.1063/5.0143661 (2023).

Abstract:

Far-ultraviolet-C (far-UVC) light-emitting diodes (LEDs) with an emission wavelength of 234 nm with different polarization-doped AlGaN hole injection layers (HILs) are compared regarding their emission power, voltage, and leakage current. The influence of the thickness of the polarization-doped layer (PDL), an additional Mg doping of the PDL, as well as a combination of a PDL with a conventionally Mg-doped AlGaN HIL will be discussed. The different PDL thicknesses show nearly no influence on the emission power or voltage. However, the leakage current of the LEDs below the turn-on voltage decreases with an increasing thickness of the PDL. In contrast, an additional Mg doping of the PDL ([Mg] ∼ 1.5 × 10¹⁹ cm^-3) results in a fivefold decrease in the emission power at an unchanged voltage and leakage current. Finally, a combination of a PDL and a conventionally Mg-doped AlGaN layer ([Mg] ∼ 1.5 × 10¹⁹ cm^-3) as a HIL shows also a similar emission power and voltage compared to the single PDL, but the leakage current increases. Based on these optimizations, 234 nm LEDs were realized with a maximum external quantum efficiency of 1% at 20 mA, an emission power of 4.7 mW, and a voltage of 9.0V at 100 mA. This shows that the polarization doping concept is well suited to realize far-UVC LEDs with improved performance compared to LEDs with a conventionally Mg-doped p-side.

© 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0143661
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