Introduction
Recently, a team led by Professor Zhou Shengjun at Wuhan University developed a novel Schottky-contact intrinsic current blocking layer (SCBL) to enhance current diffusion in the active region and improve the light extraction efficiency (LEE) of AlGaInP red Mini LEDs.
Device Structure and Manufacturing Process
The images above illustrate (a) the device structure, and (b) the manufacturing process flow for AlGaInP red Mini LEDs featuring the SCBL. Panels (c) and (d) show optical microscope images of the top view of the SCBL and AlGaInP red vertical structure Mini LEDs, respectively.
SCBL Development
Professor Zhou explained that the team constructed the SCBL using the Schottky contact properties between indium tin oxide (ITO) and p-GaP, along with the ohmic contact characteristics of ITO and p-GaP+. This was demonstrated using the transfer length method.
Impact on Light Extraction Efficiency
The SCBL effectively alleviates current crowding around the p-electrode, promoting uniform current diffusion, which enhances the light extraction efficiency of AlGaInP red Mini LEDs. With improved current diffusion and light extraction, Mini LEDs featuring the SCBL exhibit a more uniform light intensity distribution, higher optical output power, and increased external quantum efficiency (EQE).
Importance of AlGaInP Red Mini LEDs
AlGaInP red Mini LEDs are widely used in full-color displays due to their high brightness, low energy consumption, and long lifespan. However, current crowding around the p-electrode leads to uneven current distribution within the active region. Additionally, most photons generated in the active region are absorbed or reflected by the opaque metal p-electrode, resulting in low light extraction efficiency.
Solution with SCBL
To address these issues, the researchers introduced the SCBL to enhance current diffusion and light extraction in AlGaInP-based Mini LEDs. By utilizing a Schottky contact between ITO and p-GaP, the SCBL prevents current crowding around the p-electrode. Instead, the current is forced through the p-GaP+ ohmic contact layer into the active region, avoiding the absorption and reflection of light by the opaque metal p-electrode.
Results
The results indicate that compared to AlGaInP-based Mini LEDs without SCBL, those utilizing SCBL show an increase in external quantum efficiency (EQE) of up to 31.8% at a current of 20 mA. Thus, SCBL technology is expected to be applied in the mass production of efficient AlGaInP-based red Mini LEDs.
Related Achievements
Notably, Professor Zhou’s team at Wuhan University has also published multiple new findings in LED research. For instance, in the field of deep ultraviolet LEDs, they introduced a 26 nm AlGaN-based ultra-thin tunneling junction, improving the electro-optical conversion efficiency of deep ultraviolet LEDs by 5.5%. In the Mini LED sector, they enhanced the performance of blue and green inverted Mini LED chips by using a Full-angle Distributed Bragg Reflector (DBR). Under a 10 mA injection current, the optical output power of the ITO/DBR-based blue and green Mini LEDs increased by approximately 7.7% and 7.3%, respectively.
Disclaimer: The views and opinions expressed in this article are those of the original authors and do not necessarily reflect the official policy or position of MiniMicroLED Insights . While we strive to ensure the accuracy and reliability of the information provided, the content on this website may include translations, re-edited versions of second-hand information, or information derived from unverifiable sources. MiniMicroLED Insights makes no representations or warranties, express or implied, regarding the completeness, accuracy, or timeliness of such content. The information in this article is for informational purposes only and should not be construed as professional advice. Any reliance you place on such information is strictly at your own risk. To the fullest extent permitted by law, MiniMicroLED Insights disclaims all liability for any direct, indirect, incidental, consequential, or punitive damages arising out of your use of, or reliance on, the information contained in this article.
Copyright Notice: This article may include translated and re-edited content derived from various online sources, including websites and social media platforms. While we strive to credit the original authors and sources to the best of our ability, we may not always be able to verify the original source of the content. All rights to the original content remain with the original author or source publication. Where applicable, this content is reproduced for educational and informational purposes under the fair use doctrine. If you believe any content on this site infringes upon your intellectual property rights, or if you are the copyright owner and believe we have not credited you correctly, please contact us at minimicroled.business@gmail.com. We will investigate and take corrective action, including removing or properly crediting the content if necessary.
Content sourced and adapted by MiniMicroLED Insights (Doris).