Research and Development of AlGaN-based Far-UVC LED for a Greener Society
Farmroid with experience in the field of biotechnology and band engineering of AlGaN/GaN/AlN materials, will struggle for UV Technologies to provide clean and safe living environment. The next-generation semiconductor technology such as AlGaN-based Far-UVC LED technology is developed in collaboration with RIKEN. The part of AlGaN-based Far-UVC LED technology of Farmroid is originated from Riken, Japan in 2020. Hirayama Quantum Optodevice Laboratory Riken Cluster for Pioneering Research has long history of AlGaN/GaN – based UV LED technologies (more info) on low-cost AlN template (NH3 pulsed-flow growth method) on c-Sapphire substrate for realizing a high output power and world record efficiency of 20% for DUV and 9.6% for UVB devices (more info). Mutually developed UV devices (more info) will be tested for germicidal and virucidal inactivation to ensure the inactivation of germs and at the same time ensure the safety of living bodies including livestock. Such technological and biological investigations will be carried out at Nihon University School of Medicine and Tokyo University of Agriculture and Technology (TUAT), Tokyo.
Farmroid being a responsible organization is striving to
contribute towards the 17 Sustainable Development Goals of the United Nations (17 SDGs) [https://sdgs.un.org/goals]. Our priority is to contribute for Goal # 03 (Good Health and Well-Being), Goal # 06 (Clean Water and Sanitation), Goal # 7 (Affordable and Clean Energy), and Goal # 13 (Climate Action) through bioengineering and UV-photonic as well as Band engineering technologies, using Green AlGaN materials as well as green process.
Our philosophy of green technologies for nature:
- By preventing the spread of infectious diseases to the extent possible by sterilization through UV Technology, thus ensuring a safe living environment.
- By providing clean and safe drinkable water, clean air to breathe and safe food to eat, after inactivating the germs and viruses via safe and green UV Technology.
- By developing UV technologies that ensure safe and well-being of all living bodies without any harmful effect.
- By replacing the currently available UV light sources of excimer laser lamp or toxic mercury UV lamp, which is causing air, water, soil pollution as well as contaminations.
These big sized Hg-based UV lamps can emit CO2 and consume huge amount of energy which is the critical concern of Climate Change under the guideline of 13th SDG. Moreover, Minamata experienced a severe, mercury poisoning after industrial wastewater (Methylmercury) was discharged into Minamata Bay in 1950. Chisso-Minamata –byō (チッソ水俣病), is a neurological syndrome caused by mercury poisoning. Therefore, the Minamata Convention was named after the Japanese city of Minamata, and it was signed in Kumamoto on October 10, 2013. Later in 2020, it was agreed among the member nations to stop the use of Mercury (Hg)resources. This is called Minamata Convention of 2020 [https://www.mercuryconvention.org/en]
Farmroid’s (222-230 nm)-Band Far-UVC LED technology that inactivates germs and viruses, without causing damage to other living bodies.
Impact of Far-UVC on Germs and Viruses (Sterilization and Disinfection)
As we know that a virus is a submicroscopic infectious agent that replicates inside the living cells of an organism and it infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. When UV light falls on germ / virus, it is absorbed by its DNA/RNA and then forming a dimer by covalent bonding of adjacent thymine bases. Subsequently, disrupting the sequence of bases in its RNA/DNA, thereby inferring the replication. Increase in the number of these dimers on germ’s DNA/RNA, can suppress the growth of germ making it harmless or in other terms called as inactivation of germs and viruses.
Impact of Far-UVC light on Humans
The outermost layer of human skin is Stratum corneum consisting of hard protein keratin of minimum thickness 10 to 20 µm. Since the virus is less than 0.1 µm in diameter and human skin cells are 10-30 µm in diameter, UV light of 220-230 nm penetrates the viruses and inactivates it efficiently. However, UV rays of 220 to 230 nm cannot penetrate and damage the human skin cells as it is absorbed only by the outermost hard protein layer (keratin) before it could reach to the underlying living cells.
Epitaxial Growth and Fabrication of Clean and Smart (222-230 nm)-Band AlGaN-based Far-UVC LED
Development of AlGaN-based Far-UVC LED involves an epitaxial growth using low-pressure Metal-Organic Chemical Vapour Deposition (MOCVD) and fabrication of the devices. Next, a comprehensive characterization of LED samples, i.e., including structural, optical, and electrical, and performance evaluations (light power and EQE) is attempted. Subsequently, the standard Flip-chip (FC) and package technology, including wire bonding and lens mounting on LED, are attempted. Finally, we enter into an irradiation test for germicidal and virucidal’s inactivation using a Far-UVC LED panel. Especially to understand the effect of UV for inactivation of SARS-CoV-2 samples, and at the same time tested to ensure the safety of the human body and livestock, respectively. Our ultimate goal is the standard packaging UV technology and the commercialization of smart and clean Far-UVC LED. However, in prior, we still have a few technological challenges in the AlGaN-based Far-UVC LED devices which needs to be overcome.