Public Thesis Defense of Nicolas Roisin - ICTEAM

Optical and Electrical Properties of Highly Strained Silicon towards Extended Infrared Photodetection by Nicolas Roisin

Mardi 18 février 2025 à 16h15 – Auditoire SUD19, Place Croix du Sud à 1348 Louvain-la-Neuve

This thesis explores the potential of strained silicon for infrared photodetection, addressing the inherent limitations of strained silicon. Indeed, its relatively high bandgap of 1.12 eV limits its use in optical applications for light beyond 1.1 µm wavelength. These include typical near-infrared and shortwave-infrared applications such as CO2 monitoring or optical communications, for which germanium (Ge) or indium gallium arsenide (InGaAs) photodetectors are preferred. A promising approach to overcome the silicon limitation is the use of strain engineering to modify its electronic band structure, thereby enhancing its optical and electrical properties. This study combines first-principles calculations based on density functional theory (DFT) to investigate the effects of strain on the band structure, carrier mobility and absorption properties of silicon. Experimental techniques such as Raman spectroscopy, photoluminescence and electronic measurements are used where possible to validate the theoretical predictions. In addition, technology computer-aided design (TCAD) simulations are used to evaluate the performances of strained silicon photodetectors for infrared detection. The aim of this research is to contribute to the development of silicon photodetectors capable of operating in the near-infrared spectrum, with the hope of broadening the applicability of silicon-based photonics in modern technology.
 

Jury members :
Prof. Denis Flandre (UCLouvain), supervisor
Prof. Jean-Pierre Raskin (UCLouvain), supervisor
Prof. Laurent Francis (UCLouvain), chairperson
Prof. Samuel Poncé (UCLouvain), secretary
Prof. Andrea Fiore (TU/e, Netherlands)
Prof. Beata Kardynal (Forschungszentrum Jülich, Germany)

Pay attention: the public defense of Nicolas Roisin will also take place in the form of a videoconference.