2. Research
  3. Photonics
  4. Chips - Laser & LEDs
  5. UV-LEDs

UV Light Emitting Diodes (UV-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 of our UV-LEDs 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.

Processed wafer with UV-LEDs, which is held by tweezers
Processed LED wafer
On-wafer measurement of a UVB LED wafer with an LED that emits light
On-wafer measurement of a UVB LED wafer
Single LED chips that are positioned on a gel pack
LED chips in gel pack
Single UV LED chip
Single UV LED chip
UVB LED in TO package
UVB LED in TO package
UVB LED as SMD device
UVB LED as SMD device on metal core PCB
UV LED in a silicon SMD package
UV LED in a silicon SMD package
UV LED in an aluminum nitride SMD package
UV LED in an aluminum nitride SMD package

  • 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

Multi-λ UV-LED module

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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

Epi-C

In the Epi-C project, we are developing the epitaxy of UVC LED semiconductor heterostructures. The goal is to realize LEDs with high output powers, low voltages and long lifetimes. Our focus is on the development of LEDs in the spectral region of 250 nm – 260 nm and 225 nm – 235 nm, which can be used, for example, to replace low-pressure mercury vapor lamps and for antiseptic wound treatment. For this purpose, we are developing, among other things, a suitable AlN/sapphire template technology as well as structures and growth processes for efficient injection and radiative recombination of charge carriers.

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

Selected Publications