Competitive devices – UVC LEDs with high injection efficiency


Output power, voltage, and spectrum of a 265nm LED
Output power, voltage, and spectrum of a 265nm LED mounted in flip-chip geometry on an AlN ceramic submount

Our partners Technische Universität Berlin and Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik (FBH) have started to develop UV LEDs emitting around 265 nm and achieved competitive devices by carefully optimizing the current injection efficiency within the framework of the project »Highly efficient UVC LEDs. All LED structures were based on epitaxially laterally overgrown (ELO) AlN-templates on sapphire, whose threading dislocation density is reduced in comparison to conventional planar AlN templates. Thisallowed for an enhanced radiative recombination. The injection efficiency could be significantly improved by varying the heterostructure of the electron blocking layer (EBL). An interlayer (IL) between the EBL and the last barrier of the active region was inserted and the aluminum content as well as the thickness were varied. The evaluation of the complete LED wafer was conducted by electroluminescence spectroscopy, in which indium was used for the  p- and n-contacts. An LED without IL didn’t show significant luminescence from the quantum well (QW) active region, while an LED with an 1.5 nm thick AlN IL yielded approximately 1 mW output power at 60 mA injection current. A further increase of the IL thickness did not lead to higher output power. By varying the Al content of the IL between 85 and 100%, a maximum in the emission power at 92% Al content was found with 1.3 mW output power at 60 mA.

EpiTT Gen3: high temperature AlN templates for UV LEDs


In the course of its cooperation with in-situ metrology system maker LayTec AG of Berlin, Germany in the consortium 'Advanced UV for Life', the group of professor Markus Weyers at Berlin-based Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) has developed a high-temperature (HT) metal-organic chemical vapor deposition (MOCVD) process for growing low-defect-density aluminium nitride (AlN)/sapphire templates for ultraviolet light-emitting diodes (UV LEDs).

LayTec's research target is the next generation technology for UV-B and UV-CIII-Nitride-based LEDs. Starting with Q1/2016, LayTec will ship in-situ metrology tools (EpiTT, EpiCurve® TT and Pyro 400) as part of the new and modular Gen3 class. This 3rd generation of in-situ metrology offers a whole number of significant technology advances and is moreflexible in customization to the needs of specific epitaxy processes.

Further information in »Semiconductor Today

Publication "Photonics in Germany 2015"


The Publication "Photonics in Germany 2015" provides valuable information on research and development in optical technologies, pointing to the German research strength and gives an overview of possible contact for further cooperation between science and industry.

Michael Kneissl from Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik explains the challenges in the development of UV LEDs and their utility in numerous applications. He also appoints Advanced UV for Life as an important network of research institutions and companies, which aims to significantly advance the development of UV LEDs. »More...

Besides this Article two consortium partners are represented.

The Ferdinand-Braun-Institut is named as a strong partner for research and industry and the world's leading institute for optoelectronics. An important area of research are the UV LED chips. From material processing to applications in medicine, sensors, and in space - Diode lasers and UV LEDs based on research results of the Institute are key components in a variety of applications. »More...

In addition, Sentech Instruments GmbH is named as an expert in thin film metrology and plasma process technology. The focus is on the ALD Real Time Monitor, which is especially suitable for nanotechnology and microsystems applications, inorganic and organic semiconductor technology and for equipment passivation. »More...

For the whole publication "Photonics in Germany 2015" click »here.

Growing Consortium


The inclusion of eight new partners in the consortium has been agreed:

  • Analytik Jena AG
  • Asclepion Laser Technologies GmbH
  • Courage+Khazaka Electronic GmbH
  • Hans Karrer GmbH
  • Leibniz Institute for Natural Product Research and Infection Biology- Hans Knöll Institutemicro resist technology GmbH
  • Physikalisch-Technische Bundesanstalt
  • TZW: DVGW - Technologiezentrum Wasser

Especially the fields Environment & Life Sciences and Medicine will be supported by the new partner. Furthermore the fields Water and Module & Metrology will be strengthened.

By now Advanced UV for Life includes 31 partner, with 13 research institutions and 18 companies.

For more information about the partners click »here.