UV Light Emitting Diodes (LEDs)

We develop (In)AlGaN-based light-emitting diodes (LEDs) with emission in the ultraviolet (UV) spectral region. The research work takes place in close cooperation with the TU Berlin within the Joint Lab GaN Optoelectronics. Activities include device simulation, design, epitaxy of (InAlGa)N heterostructures, device chip fabrication, assembly and characterization.

Advantages at a glance

  • emission wavelength can be adjusted to the respective application by adapting the heterostructure
  • small, compact and robust
  • can be operated at low voltages (mobile applications)
  • can be switched quickly
  • do not contain toxic substances

Thanks to these properties, UV LEDs are already superior to conventional UV emitters such as mercury-based gas discharge lamps in many respects. As technology advances, the advantages of UV LEDs will continue to increase.

  • 300-320 nm for surface polymerization, phototherapy and plant irradiation, typ. light output power 25 mW (350 mA)
  • 260-280 nm for water, air and surface disinfection, typ. light output power 18 mW (350 mA)
  • 250-260 nm for spectroscopy, typ. light output power 9 mW (350 mA)
  • 225-235 nm for gas sensing and skin tolerant UV antiseptics, typ. light output power 1.5 mW (200 mA)

Our best UV LEDs achieve up to twice the light output power as specified above. Together with our in-house Prototype Engineering Lab, we assemble our UV LEDs into lamp modules and complete irradiation systems. We test these with partners in practical applications such as plant irradiation or wound and skin disinfection.

  • simulation of the LED heterostructure
  • epitaxial deposition of the (InAlGa)N heterostructures on different MOVPE machines
  • chip technology in the process line of the FBH clean room (including monolithically integrated gold micro-stud-bumps for subsequent flip-chip assembly via thermocompression)
  • assembly of LED chips in SMD packages made of AlN ceramics or crystalline silicon, which can be sealed with lens covers
  • characterization (including measurement of the power-current-voltage characteristics as well as their spectra on-wafer or on the mounted chip, detailed aging studies to analyse possible degradation mechanisms)
The full UV LED value chain – a look behind the scenes at FBH's laboratories and manufacturing steps

Our current projects

CORSA

In the joint project CORSA*, SARS-CoV-2 and other respiratory viruses on surfaces and skin are to be inactivated by the use of UVC light. For this purpose, the FBH project team is developing special UVC LEDs with very short wavelengths and suitable irradiation systems. We supply these to the project partners, who investigate the efficiency of the UV-induced inactivation process as a function of wavelength, irradiation dose and virus habitat.

* Inactivation of SARS-CoV-2 by UVC light and compatibility for humans

DINoLED

In the DINoLED* project, a DIN standard is being developed that will lay the legal and normative foundations for drinking water treatment using UV light from LEDs. This is necessary because so far only mercury vapor gas discharge lamps have been approved for such treatments in Germany. FBH contributes its expertise in the field of UV LEDs, investigates typical available UVC LEDs on the market and supports the project partners with the obtained data as well as in the development of the draft standard.

* Development of a draft DIN standard for UV-LED-based water disinfection devices in public drinking water treatment

OLAV

In the OLAV* project, the suitability and stability of encapsulation materials already available on the market as well as newly produced materials for the encapsulation of UVB and UVC LEDs will be investigated. For this purpose, we provide 265 nm and 310 nm LEDs to the project partners. We perform the electro-optical characterization of the LEDs with and without encapsulation and investigate the degradation behaviour of the encapsulation materials during LED operation.

* UV LEDs with optimized light extraction through adapted encapsulation technology

ULTRA.sens

In the ULTRA.sens* project, photometric UV gas analyser’s based on UV LEDs are to be realized to detect gases such as nitrogen oxides, sulfur dioxide or hydrogen sulfur with detection limits < 1 ppm. For this purpose, we are developing in cooperation with the TU Berlin far-UVC LEDs (emission wavelength = 226 nm) with a sufficiently high efficiency and reliability for use in low-maintenance mobile gas analysers. We are also developing the LED emitter unit using LEDs of other wavelengths in addition to the far-UVC LEDs.

* UV gas analysis based on innovative UV LEDs and UV LED arrays

UVPower

In the UVPower project, we are developing epitaxy and chip technology for UVB and UVC LEDs with high output powers together with our project partners. FBH is responsible for the UVB range around 310 nm. Among other things, we are developing adapted wafer front-end and back-end processes - such as UV-reflective contacts and a laser lift-off of the substrate - which should significantly increase the light extraction compared to the current state.

VIMRE

In the VIMRE* project, FBH is developing irradiation systems based on far-UVC LEDs. The project partners from the field of medicine want to prove that this radiation is suitable to kill microorganisms and especially multi-resistant pathogens. At the same time, they want to show that the radiation is harmless to humans if you adhere to certain radiation dose levels. The (230 ± 5) nm LEDs used in the systems are manufactured at FBH in collaboration with TU Berlin.

* Prevention of infection with multi-resistant pathogens via in-vivo UVC irradiation