POLYMETIS

“ἐν δ᾽ ἀρχὸς ἔβη πολύμητις Ὀδυσσεύς.”

- Homer, Illiad, Book 1, line 311

 

The POLYMETIS group borrows its name from one of the homeric epithets most often associated to Odysseus: πολύμητις - the one of many wiles or talents. The name reflects the group's aspiration to conduct research in semiconductor materials that are key in various fields of applied physics and technology. Innovation in these fields often requires one to think out of the box and find tricks that help us overcome hurdles encountered in developing the necessary materials, solutions found through in-depth charaerization of materials.

Our research activities focus on two main axes:

1.   Epitaxy of semiconductors for photonics using metal-organic vapor phase epitaxy

The group possesess two MOVPE reactors in the POEM platform, each equipped with 12 OM and 6 hydride sources, in which we develop several semiconductor alloys for applications in near and mid infrared photonics. Our research activities in MOVPE are further subdivided into two categories:

1. Complex heterostructures relying on mature semiconductors 
   • Vertical external cavity surface emitting lasers (VECSELs) based on (Al,Ga)As alloys on GaAs 
   • Telecom nanolasers and quantum cascade devices based on (In,Al,Ga)As alloys on InP
2. Emerging semiconductors
   • Integrated nonlinear photonics and optomechanics based on GaP
   • Active devices based direct-gap SiGeSn alloys 

2.     Quantitative transmission electron microscopy

The group has access to the PANAM platform's two TEM/STEM microscopes. We use these microscopes to quantitatively investigate the structure, composition ans strain of semiconductors and their nanosctructures. We study a wide variety of materials including:

1. III-V, II-VI, and Column IV semiconductors and their alloys in bulk structures, superlattices, nanowires, and epitaxial or colloidal quantum dots.
2. Metal-organic frameworks
3. Materials for archeology

We also study fundamental aspects of quantitative electron microscopy - most notably the quantification of the Z-contrast in HAADF-STEM images to produce atomically resolved precise mappings of composition and strain in semiconductor heterostructures.

Finally, the group has a third, transverse axis: in situ growth of epitaxial quantum dots in the Nanomax trasmission electron microscope.