Quantum Optoelectronics

Main research topics

Our activities are part of the research efforts on spin electronics and quantum technologies that are subject of strong international competition.

Our investigations on the excitonic and optical properties of two-dimensional materials based on transition metal dichalcogenides have greatly increased. We have recently made some important advances, notably on the measurement of the exciton binding energy, exciton fine structure (dark and bright states), the characteristics of the excited states, the dielectric screening effects, the radiative recombination dynamics , Auger effects, spin / valley relaxation mechanisms …

In addition to the stationary or time-resolved optical spectroscopy measurements that are the specialty of the team, the novelty here was the development of sample production benches and the manufacture of devices. These efforts have resulted in very high quality samples and a very fast process between physical ideas, manufacturing and measurement.

We are also continuing our extensive studies on spin properties in several directions:

(a) Electrical spin injection or detection in III-V ferromagnetic / semiconductor hybrid structures (Spin-LED or Spin-photocurrent) with the first devices operating without external magnetic field;

(b) Spin-dependent recombination effects in GaAsN or Gallium-implanted GaAs-type materials, particularly with the demonstration of highly original electron-nuclei coherent spin oscillations;

(c) Spin-orbit engineering and its consequences on spin dynamics in GaAsBi / GaAs structures;

(d) Optical orientation and spin dynamics in semiconductors IV: Ge or GeSn on silicon.

In parallel, the expertise acquired in the team is valued in more applied research, in collaboration with public or industrial partners. These research contracts concern in particular: optical telecommunications (band structure engineering for semiconductor amplifiers with Nokia Bell Labs, III-V Lab and APEX Technologies); electronic devices for space (study of the effects of irradiation via the development of ultrafast laser irradiation benches with the SME TRAD); nanomaterials for photovoltaics and photocatalysis (Cu2ZnSnS4 and WSe2 with CIRIMAT in Toulouse).