From Sand to Quantum Computing
Quantum computing demands an entirely new level of processing power, but current production methods are massive, complex, and expensive. What if there were a way to build quantum computers that’s faster, simpler, and more affordable? Watch PhD student Maximilian Oezkent from the Leibniz-Institut für Kristallzüchtung (IKZ) hack into our current understanding of quantum technology.
What Makes Quantum Processors Unique?
Such quantum processors are incredibly sensitive to material defects, requiring ultrapure, high quality materials. These processors depend on “quantum-grade” silicon and germanium structures to function reliably, which is one of the biggest challenges in quantum computing today. So, how can we create materials that meet these exacting standards?
Advanced Growth Techniques
In order to achieve quantum grade crystals, the Leibniz-Institut für Kristallzüchtung (IKZ) has recently installed a state-of-the-art molecular beam epitaxy (MBE) system, facilitating the epitaxial growth of ultra-pure, isotopically enriched Ge/Si thin films grown in ultra-high vacuum (less than one trillionth of an atmosphere, 10-11 mbar) conditions. With this, a provision of a novel platform of nuclear spin-free materials, which are particularly advantageous for quantum device applications is possible.
Quantum Spin Control
One of our primary goals is to implement a hole-spin qubit within a germanium quantum well layer (QWL). For this, we grow a nuclear-spin-free 28Si0.276Ge0.8/76Ge QWL/28Si0.276Ge0.8 heterostructure. We achieve a fully strained QWL that maintains high chemical and isotopic purity and structural quality, even above the critical thickness (< 14 nm).
Investigative Techniques and Challenges
We analyze the heterostructure with advanced techniques like Atom Probe Tomography (APT), X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Secondary Ion Mass Spectrometry (SIMS), Raman Spectroscopy, and Transmission Electron Microscopy (TEM). Special attention is given to studying the top interface (< 1 nm) of the QWL, as the quality of this interface has a direct impact on the quantum properties, such as the g-factor.
Beyond Quantum Computing
The ability to produce isotopically pure, high-purity layers with excellent structural quality also lays the groundwork for developing additional quantum technologies, supporting advancements beyond quantum computing itself.
Presented by
Maximilian Oezkent, SiGe-based Quantum Materials & Crystallography at Leibniz-Institut für Kristallzüchtung (IKZ)