Scalable synthesis of spatially confined Ge quantum dots with tunable quantum confinement

We report a scalable, thermodynamically guided method for synthesizing germanium quantum dots embedded in a silicon oxide matrix with nanometer-scale precision. By engineering the oxidation and annealing conditions of silicon-germanium alloy layers, we achieved spatially confined, crystalline germanium quantum dots as small as 9.2 nanometers with tunneling oxide thicknesses down to 3.2 nanometers-suitable for room-temperature quantum confinement. Molecular dynamics simulations across a range of germanium compositions predict the agglomeration behaviour and size evolution of the quantum dots, while an analytical model enables predictive tuning of quantum dot dimensions and oxide thickness based on their initial alloy composition. Experimental validation using scanning transmission electron microscopy, X-ray diffraction, and photoluminescence spectroscopy confirms crystallinity and size-dependent optical emission in the visible range. In contrast to earlier nanocrystal memory systems that relied on randomly distributed germanium precipitates embedded deep in thick oxides, our method enables precise formation of shallow, single-layer quantum dots with controlled geometry. These findings establish a robust platform for room-temperature quantum dot electronics, combining tunable confinement and compatibility with integrated circuit architectures.