Semiconductors

A semiconductor is a substance, usually a solid chemical element or compound, that can conduct electricity under some conditions but not others, making it a good medium for the control of electrical current. Its conductance varies depending on the current or voltage applied to a control electrode, or on the intensity of irradiation by infrared (IR), visible light, ultraviolet (UV), or X rays.

  • 30.2 Percent Efficiency – New Record for Silicon-based Multi-junction Solar Cell

    Wafer-bonded III-V / Si multi-junction solar cell with 30.2 percent efficiency. ©Fraunhofer ISE/A. Wekkeli

    Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with the Austrian company EV Group (EVG) have successfully manufactured a silicon-based multi-junction solar cell with two contacts and an efficiency exceeding the theoretical limit of silicon solar cells. For this achievement, the researchers used a “direct wafer bonding” process to transfer a few micrometers of III-V semiconductor material to silicon, a well-known process in the microelectronics industry. After plasma activation, the subcell surfaces are bonded together in vacuum by applying pressure. The atoms on the surface of the III-V subcell form bonds with the silicon atoms, creating a monolithic device.

  • A Material with Promising Properties

    Picture of a hybrid particle taken by a transmission electron microscope. Pictured are the inorganic (dark) and organic (light) lamellas that the particle is made of, as well as the tubular shapes (the low-contrast area in the middle). Through vaporisation with Europium, the hybrid stage can be transformed into pure EuO. Copyright: University of Konstanz

    Konstanz scientist synthesises an important ferromagnetic semiconductor. The Collaborative Research Centre CRC 1214 at the University of Konstanz has developed a method for synthesising Europium (II) oxide nanoparticles - a ferromagnetic semiconductor that is relevant for data storage and data transport. Ferromagnetic semiconductors have attracted increasing attention over the last decade. Their properties make them promising functional materials that can be used in the field of spin-based electronics (spintronics). Spintronics is of crucial importance for the storage and transport of information.

  • A new spin on electronics

    The spin of electrons transports information in this conducting layer between two isolators. Image: Christoph Hohmann / NIM

    Interface between insulators enables information transport by spin.
    Modern computer technology is based on the transport of electric charge in semiconductors. But this technology’s potential will be reaching its limits in the near future, since the components deployed cannot be miniaturized further. But, there is another option: using an electron’s spin, instead of its charge, to transmit information. A team of scientists from Munich and Kyoto is now demonstrating how this works.

  • Advanced X-ray Topography Tool Offers More Insights into Semiconductor Material Quality

    X-ray transmission topogram of the 101 reflex for a full 100 mm 4H SiC wafer and a more detailed section of the wafer. Fraunhofer IISB

    Fraunhofer IISB and Rigaku Europe SE are starting a strategic partnership in order to support the European semiconductor industry in improving and better understanding their wafer quality and yield by employing the Rigaku XRTmicron advanced X-ray topography tool. Rigaku Europe SE and Fraunhofer IISB in Erlangen are pleased to announce the formation of a strategic partnership to revolutionize the characterization of semiconductor materials by X-ray topography; therefore, Rigaku has installed the latest generation X-ray topography tool, the Rigaku XRTmicron imaging system, at Fraunhofer IISB.

  • Carbon Nanotubes Couple Light and Matter

    The formation of exciton-polaritons through strong light-matter coupling is a promising strategy for producing electrically pumped carbon-based lasers. Scientists from Heidelberg University and the University of St Andrews (Scotland) have now, for the first time, demonstrated this strong light-matter coupling in semiconducting carbon nanotubes. Figure: Arko Graf (Heidelberg University)

    Scientists from Heidelberg and St Andrews work on the basics of new light sources from organic semiconductors. With their research on nanomaterials for optoelectronics, scientists from Heidelberg University and the University of St Andrews (Scotland) have succeeded for the first time to demonstrate a strong interaction of light and matter in semiconducting carbon nanotubes. Such strong light-matter coupling is an important step towards realising new light sources, such as electrically pumped lasers based on organic semiconductors. They would be, amongst other things, important for applications in telecommunications. These results are the outcome of a cooperation between Prof. Dr Jana Zaumseil (Heidelberg) and Prof. Dr Malte Gather (St Andrews), and have been published in “Nature Communications”.

  • Cfaed Researchers of TU Dresden Uncover Doping in Organic Semiconductors

    Geometry of a molecular cluster of dopant and host molecules with benzimidazoline dopant and a C60 molecule. S. Schellhammer/ F. Ortmann

    A group of physicists from the cfaed at TU Dresden, together with researchers from Japan, were able to demonstrate in a study how the doping of organic semiconductors can be simulated and experimentally verified. The study has now been published in “Nature Materials”. In semiconductor technology, doping refers to the intentional introduction of impurities (also known as dopants) into a layer or into the intrinsic semiconductor of an integrated circuit.

  • Energy-saving New LED Phosphor

    The crystal structure of the SALON phosphor is the reason for its excellent luminescence properties. Uni Innsbruck

    The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.

  • Further Improvement of Qubit Lifetime for Quantum Computers

    Illustration of the filtering of unwanted quasiparticles (red spheres) from a stream of superconducting electron pairs (blue spheres) using a microwave-driven pump. Philip Krantz, Krantz NanoArt

    New Technique Removes Quasiparticles from Superconducting Quantum Circuits - An international team of scientists has succeeded in making further improvements to the lifetime of superconducting quantum circuits. An important prerequisite for the realization of high-performance quantum computers is that the stored data should remain intact for as long as possible. The researchers, including Jülich physicist Dr. Gianluigi Catelani, have developed and tested a technique that removes unpaired electrons from the circuits. These are known to shorten the qubit lifetime (to be published online by the journal Science today.

  • Goodbye, Silicon? On the Way to New Electronic Materials with Metal-organic Networks

    A metal-organic framework could serve as a replacement for the semiconductor silicon in the future. © MPI-P

    Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

  • High-performance Roll-to-Roll processing for flexible electronics

    Ultra-thin flexible Corning® Willow® Glass with a glass thickness of 100 μm © Fraunhofer FEP, Photographer: Jürgen Lösel

    Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP as one of the leading partners for research and development for surface technologies and organic electronics presents a roll of flexible thin glass, which is coated with highly conductive ITO continuously on 100 meters with roll-to-roll technology for the first time at FLEX 2017, from June 19 – 22, 2017 in Monterey, USA at booth no. 1004.

  • How to Design Efficient Materials for OLED Displays

    Charges in organic semiconductors can be trapped by either oxygen or water molecules. © D. Andrienko, MPI-P

    For applications such as light-emitting diodes or solar cells, organic materials are nowadays in the focus of research. These organic molecules could be a promising alternative to currently used semiconductors such as silicon or germanium and are used in OLED displays. A major problem is that in many organic semiconductors the flow of electricity is hampered by microscopic defects. Scientists around Dr. Gert-Jan Wetzelaer and Dr. Denis Andrienko of the Max-Planck-Institute for Polymer Research have now investigated how organic semiconductors can be designed such that the electric conduction is not influenced by these defects.

  • Humboldt Fellowship for research on tunable optical surfaces for Terahertz technology

    Dr. Corey Shemelya. Thomas Koziel/TU Kaiserslautern

    U.S. scientist Dr. Corey Shemelya has recently started a research stay at the University of Kaiserslautern in the form of a fellowship granted by the Alexander von Humboldt Foundation. Dr. Shemelya is studying structured optical surfaces which hold potential applications in communication technology and Terahertz imaging, e.g. body scanning equipment for airport safety. Shemelya is working in conjunction with the Terahertz Technology Laboratory of Professor Marco Rahm at the Department of Electrical and Computer Engineering and the State Research Center for Optical and Material Sciences (OPTIMAS).

  • IHP brings INFOS conference to Germany

    Improvement of Silicon ICs by dielectrics: At the INFOS conference about 80 international scientists and engineers  will exchange their expertises about dielectrics and silicon circuits. © IHP/ 2017

    International conference unites engineers, technologists, material researchers, physicists and chemists in Potsdam - Their focus is on Insulating Films on Semicondoctors.

    Frankfurt (Oder). In June 2017, engineers, technologists, material researchers, physicists and chemists will meet in Potsdam. It is the first time that the international conference “INFOS” will be performed in Brandenburg. The Leibniz-institute IHP innovations for high performances microelectronics, located in Frankfurt (Oder), is organising the meeting, where experts from Europe, Asia and America will exchange their expertises on Insulating Films on Semicondoctors (INFOS).

  • IHP presents the fastest silicon-based transistor in the world

    The cross section shows a SiGe HBT of the latest generation, recorded by a TEM. The measurement curves are used to determine the transit frequency and the maximum oscillation frequency. © IHP 2016

    Frankfurt (Oder)/San Francisco. Scientist Dr. Bernd Heinemann of IHP – Innovations for High Performance Microelectronics will present results on silicon-germanium heterobipolar transistors (SiGe HBTs) developed in Frankfurt (Oder) on the “International Electron Devices Meeting” (IEDM) in San Francisco. His contribution titled “SiGe HBT with fT/fmax of 505 GHz/720 GHz “ presents speed parameters that set new standards for silicon transistors. “To present at IEDM is a valuable conclusion of the project ‘DOTSEVEN’, funded by the European Union. Together with Infineon and twelve other project partners from a total of six countries, the four-year project focused on developing SiGe HBTs with a maximum oscillation frequency, which is also referred to as fmax, of 0.7 THz,” says Dr. Bernd Heinemann, project manager at IHP.

  • Improvement of the operating range and increasing of the reliability of integrated circuits

    The invention is especially advantageous for oscillator circuits that are installed in radar devices for automotive assistance systems, for example. Foto: TLB GmbH

    Fast integrated circuits (ICs) are used in many ways in applied electronics. Especially, for hard driven fast or high-power components in the circuit, however, there is often a risk of breakdown, e.g. in oscillator circuits (radar systems, etc.) or “smart power” circuits. At the pn junctions present in all components, the breakdown occurs starting at a critical field strength. The circuit is thus destroyed or becomes unusable. A photodiode-controlled feedback prevents breakdown at pn junctions.
    TLB GmbH supports the University of Stuttgart in patenting and marketing its innovation.

  • Making spintronic neurons sing in unison

    Johan Åkerman. Photo: Johan Wingborg

    What do fire flies, Huygens’s wall clocks, and even the heart of choir singers, have in common? They can all synchronize their respective individual signals into one single unison tone or rhythm. Now researchers at University of Gothenburg have taught two different emerging classes of nano-scopic microwave signal oscillators, which can be used as future spintronic neurons, to sing in unison with their neighbours. Earlier this year, they announced the first successful synchronization of five so-called nano-contact spin torque oscillators. In that system, one of the nano-contacts played the role of the conductor, deciding which note to sing, and the other nano-contacts happily followed her lead.

  • Marcus Regime in Organic Devices: Interfacial Charge Transfer Mechanism Verified

    Device schematics. a - Schematic cross section of the device. b - Hot-electron transistor operation. Electrons are injected by applying a negative emitter-base bias, and detected in the molecular semiconductor. These electrons are out of equilibrium with the thermal electrons in the base which cannot be described by a larger temperature. The measurements can be performed either without or with externally applied collector-base bias. Frank Ortmann

    Physicists from the Research Cluster Center for Advancing Electronics Dresden (cfaed) of the TU Dresden, together with researchers from Spain, Belgium and Germany, were able to show in a study how electrons behave in their injection into organic semiconductor films. Simulations and experiments clearly identified different transport regimes. The study was published now in Nature Communications.

  • Molecular Lego for nanoelectronics

    Simulation result for formation of inversion channel (electron density) and attainment of threshold voltage (IV) in a nanowire MOSFET. Note that the threshold voltage for this device lies around 0.45V. © By Saumitra R Mehrotra & Gerhard Klimeck, modified by Zephyris - Own work

    The ability to assemble electronic building blocks consisting of individual molecules is an important objective in nanotechnology. An interdisciplinary research group at Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) is now significantly closer to achieving this goal. The team of researchers headed by Prof. Dr. Sabine Maier, Prof. Dr. Milan Kivala and Prof. Dr. Andreas Görling has successfully assembled and tested conductors and networks made up of individual, newly developed building block molecules. These could in future serve as the basis of components for optoelectronic systems, such as flexible flat screens or sensors.

  • Neues Licht dank Nanostrukturen

    Neues Licht dank Nanostrukturen © Universität Duisburg Essen

    Künftig sollen sie das Innere der Handtasche erhellen oder abendliche Jogger aus dem Dunklen hervorheben: Lichtemittierende elektrochemische Zellen, LECs, bieten gegenüber den bekannten LEDs viele Vorteile, aber noch hapert es – ja, am rechten Licht. Bisher sind nur gelb leuchtende LECs geeignet für den realistischen Einsatz. Für neutraleres Licht braucht man aber mindestens eine weitere Lichtfarbe. Forscher vom Center for Nanointegration (CENIDE) der Universität Duisburg-Essen (UDE) konnten nun erstmals die Farbe gezielt verändern und gleichzeitig die Leistungsfähigkeit der LECs steigern.

  • New Hybrid Semiconductor Material for Sustainable Hydrogen Production

    Electron microscopic image of the hybrid material. Image: Pawan Kumar / University of Alberta

    Chemists at the Technical University of Munich (TUM) have developed an efficient water splitting catalyst as part of a collaborative international research effort. The catalyst comprises a double-helix semiconductor structure encased in carbon nitride. It is perfect for producing hydrogen economically and sustainably. An international team led by TUM chemist Tom Nilges and engineer Karthik Shankar from the University of Alberta have now found a stable yet flexible semiconductor structure that splits water much more efficiently than was previously possible.