Speaker
Description
Metals are the plasmonic workhorse, but their response is largely fixed and metal/semiconductor interfaces are often defect-rich, constraining epitaxial integration. Here we demonstrate hyperdoped Ge:P as an epitaxial, semiconductor-compatible alternative whose plasma edge is dictated by the electrically active carrier density, enabling “metal-like” mid-IR reflectors with a tuneable optical response. In this context UV-ns pulsed laser melting (PLM) is used to drive ultrafast melt-recrystallization dynamics that enhance activation of in-situ Ge:P epilayers up to ~90% [1]. This high, reproducible activation renders the active density effectively adjustable via the incorporated P dose, shifting the plasma edge into the MIR [1]. Differential transport/optical analysis reveals abrupt, box-like active profiles, while laser energy density sets the activated thickness to match IR optical penetration depths [1]. Overall, in-situ growth followed by PLM delivers scalable, activation-tuneable epitaxial plasmonic layers that are overgrowth-ready for stacked absorbers, including multi-quantum-well architectures [2].
[1] G. M. Spataro et al., “Hyperdoping of Ge/Si and SiGe/Si epitaxial layers by UV-nanosecond laser processing,” Materials Science in Semiconductor Processing, vol. 200, p. 109928, Dec. 2025, doi: 10.1016/j.mssp.2025.109928.
[2] M. Faverzani, S. Calcaterra, P. Biagioni, and J. Frigerio, “Strong coupling in metal-semiconductor microcavities featuring Ge quantum wells: a perspective study,” Nanophotonics, vol. 13, no. 10, pp. 1693–1700, Apr. 2024, doi: 10.1515/nanoph-2023-0730.
Benedetta Scandolara is a PhD student in Physics in the Semiconductor Group at the Department of Physics and Astronomy “Galileo Galilei”, University of Padua. She received her M.Sc. in Materials Science, with a thesis focused on germanium hyperdoping via UV-nanosecond pulsed laser melting. Her current research investigates pulsed laser melting as a route to achieve highly doped p-type epitaxial layers using Al and Ga, with the long-term goal of accessing superconductivity in group-IV semiconductors. Her scientific interests include semiconductor epitaxy, ultrafast laser processing, dopant activation phenomena, and the electronic, optical, and emergent properties of hyperdoped materials.