Version 1
: Received: 3 August 2023 / Approved: 4 August 2023 / Online: 4 August 2023 (11:20:58 CEST)
How to cite:
Ayub, K.; Khan, B.; Sharif, M.N.; Khan, M.A.; Hirayama, H. Achieving Zero Efficiency Droop in Highly Efficient N-Polar AlGaN Tunnel Junction-based 254 nm DUV LED. Preprints2023, 2023080419. https://doi.org/10.20944/preprints202308.0419.v1
Ayub, K.; Khan, B.; Sharif, M.N.; Khan, M.A.; Hirayama, H. Achieving Zero Efficiency Droop in Highly Efficient N-Polar AlGaN Tunnel Junction-based 254 nm DUV LED. Preprints 2023, 2023080419. https://doi.org/10.20944/preprints202308.0419.v1
Ayub, K.; Khan, B.; Sharif, M.N.; Khan, M.A.; Hirayama, H. Achieving Zero Efficiency Droop in Highly Efficient N-Polar AlGaN Tunnel Junction-based 254 nm DUV LED. Preprints2023, 2023080419. https://doi.org/10.20944/preprints202308.0419.v1
APA Style
Ayub, K., Khan, B., Sharif, M.N., Khan, M.A., & Hirayama, H. (2023). Achieving Zero Efficiency Droop in Highly Efficient N-Polar AlGaN Tunnel Junction-based 254 nm DUV LED. Preprints. https://doi.org/10.20944/preprints202308.0419.v1
Chicago/Turabian Style
Ayub, K., M. Ajmal Khan and Hideki Hirayama. 2023 "Achieving Zero Efficiency Droop in Highly Efficient N-Polar AlGaN Tunnel Junction-based 254 nm DUV LED" Preprints. https://doi.org/10.20944/preprints202308.0419.v1
Abstract
Deep ultraviolet (DUV) light emitting diode (LED) at emission wavelength of 254 nm is inevitable to replace the conventional toxic mercury UV Lamp as demanded by Minamata Convention of 2020. Both the conventional DUV LEDs (C-LED) and tunnel junction (TJ)-based UVC LEDs are suffering from high operating voltages, low hole injection efficiency and efficiency droops. Therefore, p-AlGaN and n-AlGaN layers-based TJ is one of the most promising parts of optical devices and has been widely utilized as carrier tunneling in DUV LEDs to mitigate both the contact resistance for Ohmic contact and low hole injection efficicny at 254 nm emission. Here an approach is presented to electrically manipulate the quantum tunneling probability by exploiting the transported carriers at the interface of n-AlGaN/p-AlGaN TJ with moderate Si and Mg-doping levels and optimized thickness. As a result, the Augur recomination rate was sucesfully suppressed and quite high radiative recombination rates were achived in the 254nm TJ-based DUV LEDs, which is attributed the improved holes injection toward the MQWs when compared to C-LED. The internal-quantum efficiency (IQE) of approximately ~ 88% in the TJ-based LED with zero efficiency droop is achived, which is 1.3 times greater than the IQE of approximately ~ 66% in the C-LED with efficiency droop of 53%. Based on our known knowledge, this is the highest reported IQE (88%) at emission wavelength of 254 nm in the AlGaN TJ-based LED with efficiency droop of 0%. It was found that the light output powers (LOP) of TJ-LED increases linearly under the varying current density, whereas in the case of C-LED the LOP changes nonlinearly under varying current density. This is attributed to the lower Augure recombination rate in the MQWs of TJ-based DUV LED. The operating voltages were remarkable reduced from 20 V to 5.4 V under 200 mA operation, which is attributed to the thickness and doping optimization in TJ and better selection of realively lower Al-content in the contact-layer. The demonstrated TJ-based DUV LEDs opens the door to epitaxial growth of high-performance UV emitters in MOCVD and MBE for a plethora of biomedical applications.
Keywords
DUV; AlGaN; N-Polar; IQE
Subject
Physical Sciences, Applied Physics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
