Charles Cornet

InAsSb∕InP quantum dots for midwave infrared emitters: A theoretical study

A theoretical study of the electronic properties of InAsSb quantum dots (QDs) deposited on InP substrate is presented. Unstrained bulk materials present a direct gap between 0.1and 0.35eV suitable for mid-infrared emitters (2–5μm). However, strain and quantum-confinement effects may limit the extension of the emission spectrum of these nanostructures towards the higher wavelengths. Various associations of materials in the barrier are considered. Among the possible associations, InAs0.5Sb0.5∕GaAs0.5Sb0.5 QDs may provide a low-energy emission with a material system similar to the well-known InAs∕GaAs system. Other materials associations such as InAsSb∕InGaAsP∕InP are also studied. Band lineups, optical transitions, optical losses, and effective masses are computed and discussed.

Dielectric properties of hybrid perovskites and drift-diffusion modeling of perovskite cells

A method based on DFT is used to obtained dielectric profiles. The high frequency Ɛ∞(z) and the static Ɛs(z) dielectric profiles are compared for 3D, 2D-3D and 2D Hybrid Organic Perovskites (HOP). A dielectric confinement is observed for the 2D materials between the high dielectric constant of the inorganic part and the low dielectric constant of the organic part. The effect of the ionic contribution on the dielectric constant is also shown. The quantum and dielectric confinements of 3D HOP nanoplatelets are then reported. Finally, a numerical simulation based on the SILVACO code of a HOP based solar cell is proposed for various permittivity of MAPbI3.

Laser Integration Challenges

In this chapter, we provide a comprehensive overview of the ultimate properties and performances needed to truly achieve very large-scale integration of laser sources on a silicon chip. Toward this aim, the basic principles of CMOS microprocessors and the different integration schemes of a photonic layer into such architectures are first explained. Then, very simple aspects of semiconductor lasers are presented to provide the minimum prerequisites to the discussion in the next chapters. Finally, an assessment of the required quality that an integrated laser source should ideally possess is given.

Group IV Silicon Lasers

In this chapter, we present the different monolithic realizations of light emitters that have been proposed with group IV semiconductors on silicon. These approaches are of great interest as they are intrinsically compatible with photonic integration on-chip from the material point of view. But we are also faced with the inherent difficulty of working with indirect bandgap semiconductors.

III–V Lasers Bonded on Si

In this chapter, we present the different III–V laser device groups that are heterogeneously integrated on silicon through the bonding techniques. If they benefit from the state-of-the-art performances of group III–V laser devices, they also face technological issues, as well as integration constraints.

4 – Monolithic III–V Lasers on Silicon

In this chapter, we present the III–V semiconductor devices that have been monolithically integrated on silicon. Although this approach benefits from the excellent optical properties of III–V semiconductors, and a large flexibility for integration, it faces issues with regard to materials.

Laser Architectures for On-chip Information Technologies

In this chapter, we present different laser integration architectures in view of their use for on-chip information routing and processing. Some of the advantages that may be provided by on-chip photonics are also discussed.

Analysis of carriers dynamics and laser emission in 1.55-μm InAs/InP(113)B quantum dot lasers

Thanks to optimized growth techniques, a high density of uniformly sized InAs quantum dots (QD) can be grown on InP(113)B substrates. Low threshold currents obtained at 1.54 μm for broad area lasers are promising for the future. This paper is a review of the recent progress toward the understanding of electronic properties, carrier dynamics and device modelling in this system, taking into account materials and nanostructures properties. A first complete analysis of the carrier dynamics is done by combining time-resolved photoluminescence experiments and a dynamic three-level model, for the QD ground state (GS), the QD excited state (ES) and the wetting layer/barrier (WL). Auger coefficients for the intradot assisted relaxation are determined. GS saturation is also introduced. The observed double laser emission for a particular cavity length is explained by adding photon populations in the cavity with ES and GS resonant energies. Direct carrier injection from the WL to the GS related to the weak carrier confinement in the QD is evidenced. In a final step, this model is extended to QD GS and ES inhomogeneous broadening by adding multipopulation rate equations (MPREM). The model is now able to reproduce the spectral behavior in InAs-InP QD lasers. The almost continuous transition from the GS to the ES as a function of cavity length is then attributed to the large QD GS inhomogeneous broadening comparable to the GS-ES lasing energy difference. Gain compression and Auger effects on the GS transition are also be discussed.