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Atomic precision with X-STM

During her PhD research, Trevisan employed cross-sectional scanning tunneling microscopy (X-STM) to study the structural and electronic properties of these materials with atomic precision. This allowed her to identify individual antimony (Sb) atoms and analyze how they are incorporated into various semiconductor structures, such as quantum rings, superlattices, and heterojunctions.

Key findings on antimony incorporation

One of her key findings is that Sb can be homogeneously incorporated into GaAs, forming sharp compositional interfaces, an important result for the development of high-efficiency photodetectors and solar cells. She also investigated the shape and composition of GaSb quantum rings, discovering that they typically have a truncated pyramidal shape with a square central hole, and that their internal structure varies significantly between regions.

Insights into superlattices and memory devices

Trevisan鈥檚 work extended to superlattices and nonvolatile memory devices, where she examined the effects of Sb segregation and defect formation. In ULTRARAM鈩� devices, she found that while stacking faults do occur, they are unlikely to significantly impact performance, especially in designs using InAs channels.

Finally, she explored the behavior of germanium (Ge) atoms in GaAs, showing how their location within the crystal lattice affects their appearance in X-STM images. This contributes to a better understanding of amphoteric dopants in semiconductor materials.

A powerful tool for future devices

Her research demonstrates that X-STM is a powerful tool for verifying the quality of Sb-based III-V materials, which is crucial for their application in advanced semiconductor devices. As Trevisan notes, 鈥淭he performance of these devices strongly depends on their structural quality, and now we can see that quality, atom by atom.鈥�