Precision at the quantum level

Highly sensitive light sensors are needed in fields such as quantum communication, medical technology, and autonomous driving. Researchers at the University of Stuttgart's Institute of Semiconductor Engineering (IHT) have developed a germanium-based photodetector that is more cost-effective and versatile than conventional products. To make the technology market-ready, four young scientists are now launching the startup “Germanium Quantum Detectors.”

“LabOne” is written on an unassuming gray metal cube with sides measuring just eight centimeters. The prototype's housing contains cutting-edge technology designed to set new industry standards: a microchip on which four so-called “single-photon avalanche diodes” (SPADs) are interconnected. The highly sensitive light sensor can measure individual photons – the smallest particles of light – and the precise moment they arrive. Silicon photodetectors are used in many fields today, including in the 3D cameras of modern driver-assistance systems. What makes this new development – which is fully compatible with standard semiconductor manufacturing – unique is its use of small amounts of germanium. This material absorbs infrared light, which offers significant advantages in areas such as autonomous driving: Germanium-based photodetectors enable obstacles to be detected more quickly and accurately, even at greater distances and in poor visibility – a huge boost to safety.

Why aren't such detectors already in widespread use? A look inside a laboratory at the Institute of Semiconductor Engineering (IHT) at the University of Stuttgart provides the answer: there is a cooling unit about the size of a minibar, into which the prototype would fit an estimated thirty times over. Typical single-photon detectors must be cooled to nearly -270 degrees Celsius to prevent signal distortion. The innovative germanium-on-silicon photodetector achieves the same level of quality even at temperatures ranging from -10 to -20 degrees. Not only does this give it a much better cost-benefit ratio, but its compact size also makes it suitable for a wide variety of applications.

Maurice Wanitzek, who played a key role in developing the technology at the IHT, now plans to put it into practice together with three co-founders. “During my doctoral studies, many industry partners told me that they found the product interesting and would like to buy it. As an engineer, I naturally hope that my work will have a real-world application and won’t just end up gathering dust in a drawer. That insight ultimately led to the decision to found the company." To evaluate the venture’s prospects, Wanitzek approached the Technology Transfer Initiative (TTI GmbH) at the University of Stuttgart, asking them to assess its chances of success. “The result gave me confidence, and TTI was also a great help to me as I took the next steps.” A coach told him about the EXIST research transfer program and helped him prepare his application. Wanitzek also took part in workshops organized by the university’s Transfer Center (TRACES) for aspiring entrepreneurs: “This exchange was very helpful. And the fact that we had to present our ideas in ten minutes made preparing the pitch for the EXIST application much easier,” he adds.

“We support entrepreneurs with tailored advice and funding services to help them turn bold ideas into reality,” says Professor Alexander Brem, Vice Rector for Transfer and International Affairs at the University of Stuttgart. “The team at Germanium Quantum Detectors demonstrates how to drive innovation in a cutting-edge field and shows that taking the leap into entrepreneurship is well worth it.”

An EXIST grant of approximately 1.2 million euros over two years is giving the four-person entrepreneur team the momentum they need to further develop their technology until it is ready for the market. The founders – Maurice Wanitzek, an expert in microelectronics; circuit designer Jakob Finkbeiner; Claudia Bett, a physicist specializing in optics and system integration; and Dr. Maximilian Scheu, a business economist specializing in entrepreneurship – have their office at the IHT. However, they also work closely with the Institute for Microelectronics Stuttgart IMS-CHIPS. For the time being, the photodetectors will continue to be manufactured in its highly specialized cleanroom. The founders continue to take advantage of TRACES' workshop offerings, most recently on the topic of corporate law.

“We’ve allocated responsibilities within the team according to our individual areas of expertise, and we’re learning an extraordinary amount from one another,” says Claudia Bett. Despite receiving an offer from the corporate sector, she chose to join the startup: “I’d rather work independently than be told what to do. Building something new together offers a great deal of creative freedom.” We've already secured our first clients: researchers who are developing quantum cryptography applications just a few buildings away. Because the basic units of information (qubits) are transmitted via photons, they require highly sensitive light sensors.

In the next phase, the four founders plan to manufacture products for companies in the autonomous driving sector, and in the medium term, for the medical technology industry as well: their photodetectors can be used, for example, in infrared spectroscopy. The team is currently in talks with numerous companies. According to Wanitzek, the biggest challenge is finding enough customers with similar product requirements to make production economically viable: “We hope to be in the black in five years – and that our example will then inspire others to start their own businesses.”

About the founders and the Start-up Germanium Quantum Detectors
Electrical and information engineers Maurice Wanitzek and Jakob Finkbeiner, who are currently completing their doctorates at the University of Stuttgart, physicist Claudia Bett, and business economist Dr. Maximilian Scheu are working together to bring a novel photodetector to market. They are receiving 1.2 million euros in funding over two years from the “EXIST Research Transfer” program of the Federal Ministry for Economic Affairs and Energy (BMWE), which is co-financed by the European Union. In this first phase of the funding program, the founders are further developing the technology and preparing to launch their startup, “Germanium Quantum Detectors.” The team is also supported by TTI GmbH and the Transfer Center at the University of Stuttgart TRACES.