ONCHIPS Consortium to Develop Germanium-Silicon Quantum Chip

The European Commission has invested €3 million ($3.1 million) to develop a quantum chip that combines electronics and light using germanium-silicon (GeSi) technology. The goal of the project is to make quantum computers faster, more efficient and scalable, allowing them to tackle challenges like drug discovery, cybersecurity, and artificial intelligence.

Supported by the Quantum Flagship, the ONCHIPS consortium unites leading institutions from across Europe to drive technological independence and quantum innovation.

Just as the first computers of the 1950s were impractical and unsuitable for widespread adoption due to their enormous size and limited processing power, today’s quantum computers have their own challenges.

“One major issue of scalability is that qubits are often limited in their ability to interact with one another,” said project coordinator Floris Zwanenburg, a professor at the University of Twente’s MESA+ Institute for Nanotechnology. “As the number of qubits increases, effective communication between them becomes more complex.”

But GeSi, a material whose ability to efficiently emit light was only discovered in 2020, presents a viable solution to overcome these bottlenecks.

“We are combining spin qubits for computation and photonics for communication on a GeSi platform that is compatible with traditional CMOS manufacturing, which could be a total game-changer for scaling quantum computers. By combining spin qubits (electrons) with photonic communication (light), the chip bridges the gap between processing quantum information and transmitting it over long distances. This will significantly help us solve a major bottleneck in quantum scalability,” Zwanenburg said.

While GeSi has been used and studied for decades as a material system in applications like transistors in semiconductor physics, it has never been implemented in quantum computing. Scientists have worked with cubic GeSi for years and even built qubits using it, but the hexagonal light-emitting version of the material had never found its way into a quantum computer.

“In this ‘hexagonal phase’, this special structure makes the material better at giving off light. The atomic structure means it is suitable for quantum applications and photonics, where controlling light is crucial for communication, computation, and storage,” Zwanenburg said.

The team is using a monolithic integration approach to building their quantum chips, which reduces the size and complexity of the system and makes it easier to scale up, Zwanenburg said

Set to conclude in 2026, ONCHIPS brings together a consortium of leading European organisations. The partners include Universiteit Twente in the Netherlands, which coordinates the project, along with Technische Universiteit Eindhoven, Technische Universität München, Centre National de la Recherche Scientifique (CNRS), Universität Konstanz, Budapesti Muszaki és Gazdaságtudományi Egyetem, and the Dutch company Single Quantum BV.