Context: III-nitride semiconductors, GaN, AlN, and InN, have revolutionized the lighting market and are rapidly entering the power electronics sector. Currently, we are exploring new nitride compounds in the search for novel functionalities. In this context, aluminum scandium nitride (AlScN) has emerged as a particularly promising new member of the nitride family. Incorporating Sc into AlN leads to:
• Enhanced Piezoelectric Constants: This makes AlScN highly attractive for the fabrication of piezoelectric generators and high-frequency SAW/BAW filters.
• Increased Spontaneous Polarization: The heightened polarization can be utilized in designing high-electron-mobility transistors (HEMTs) with very high charge densities in the channel.
• Ferroelectricity: The recently-discovered (2019) emergence of ferroelectric properties opens up possibilities for developing new non-volatile memory devices.
Over the past five years, AlScN has become a significant focus of research, presenting numerous open questions and exciting opportunities to explore.
Target: The intern will perform a study of the growth and properties of AlScN and GaScN synthesized by molecular beam epitaxy (MBE). The student will be trained in the use of an MBE system for the synthesis of III-nitride semiconductors and in the structural characterization of materials using atomic force microscopy (AFM) and X-ray diffraction (XRD). The variation of the polarization properties of the material will be explored by analyzing the photoluminescence of quantum well structures. Finally, the student will be trained in the use of Nextnano software to perform simulations of the electronic structure of the samples, aiding in the interpretation of the optical results.
What We’re Looking For:
• A highly motivated individual passionate about experimental work in material science and nanotechnology, pursuing a Master's degree in Physics or Engineering.
• A team player with a collaborative spirit, ready to engage in multidisciplinary research.
Starting Date: Spring 2025
Supervisor: Eva MONROY

Master+PhD Position: OPEN
Characterization of the optical performance of AlGaN nanostructures for far-UV emitters

Context: The development of UV lamps has been driven by their application in disinfection, particularly effective within the spectral ranges of 260-270 nm and 220-230 nm, the latter being considered safer for human exposure. Currently these applications rely on mercurly lamps or exciment lamps. However, there is intense worldwide research to remplace them with compact, safer and more efficient solid-state devices. AlGaN is the natural semiconductor choice for this purpose, due to its direct bandgap tunable across the UVC range and the posibility of achieving both p-type and n-type conductivity.
Despite its potential, developping AlGaN-based UVC light-emitting devices presents several challenges. These include inefficient p doping, low hole mobility, alloy inhomogeneities, point defects, the presence of polarization fields, and unfavorable selection rules for carrier recombination that hinder light extraction. Achieving major improvements in efficiency requires a deeper understanding of the material's electrical and optical properties, as well as innovative band engineering in new device designs. Addressing these challenges offers an exciting research environment.
Target: The intern will join our research team in studying the optical performance of AlGaN nanostructures-including wide quantum wells, ultra-narrow quantum wells, and quantum dots-designed to serve as the active region of UVC light-emitting devices.
Targets include a quantitative a nd comparative assessment of the internal quantum efficiency and external quantum efficiency. Combining temperature and power-dependent measurements with structural charactreization, we will investigate the role of point defects, carrier localization and emissions associated with recombination form high-energy quantum confined levels.
What You'll Learn: The intern will receive comprehensive training in various photoluminescence and cathodoluminescence techniques, and structural Analysis through atomic force microscopy (AFM) and X-ray diffraction (XRD). She/he will be also trained in the use of Nextnano for electronic structure simulations.
Who We're Looking For: A highly motivated individual passionate about experimental work in materials science and nanotechnology, currently pursuing a Master's degree in Physics, Engineering, or a related field. A collaborative spirit, ready to engage in multidisciplinary research and contribute to team objectives.
Starting Date: Spring 2025
Supervisor: Eva MONROY