Highlights Opto

Group-III nitride nanowire arrays made by sublimation for nanophotonic (2019)

We have demonstrated that selective-area sublimation (carried out in a MBE chamber) together with electron beam lithography or displacement Talbot lithography can be a powerful and versatile method to realize precisely defined GaN-based NW arrays in a top-down approach.
We have shown that it not only allows for high yield and homogeneity on a macroscale but also for a fine nanoscale control in terms of position, shape, and dimensions.


AlGaN Quantum Dots for deep UV emission (2019)

As the replacement of mercury lamps by environmentally safe UV sources is required, AlGaN based LEDs are expected to fulfil this goal, in particular in the UVB (280-320 nm) and UVC (< 280 nm) regions where strategic medical and environmental applications are targeted.
As lower cost processes should be privileged, monolithic growth approaches and thin layer structures could be well adapted for the development of UV LEDs.


Tunnel better than holes (2018)

The low density of holes in GaN and even more in AlGaN induces a reduced performance of nitride LEDs.

First, access resistances increase the operating voltage and degrade the wall plug efficiency. Second, the carrier injection in the quantum well of the active region is unbalanced and its efficiency is reduced.


III-nitride on silicon nanophotonic platform: electrical injection and microlaser photonic circuits (2018)

The group III-nitrides on silicon platform is promising for photonics as it is the only one that can simultaneously combine passive and active circuits operating in the UV and visible spectral range with monolithically integrated active emitters like lasers and LEDs.


THz intersubband absorption in GaN based heterostructures grown on Silicon substrate (2018)

AlGaN/GaN heterostructures present interesting features for optoelectronic devices working in the TeraHertz (THz) range:
  • the possibility to build periodic heterostructures with energy levels separated with few tens of meV
  • a large optical phonon energy which may enable the electron population inversion in quantum cascade lasers (QCLs) at room temperature


Optical phase transition in semiconductor quantum metamaterials (2018)

The direction of refracted light at an interface between two media generally follows the conventional Snell-Descartes law. Bystacking subwavelength-thick metallic and dielectric layers to form metamaterials, it is possible to realize unexpected behavior such as negative refraction.