Many-body design of highly strained GaInNAs electroabsorption modulators on GaInAs ternary substrates

Abstract

Electroabsorption in highly strained GaInAs and GaInNAs quantum wells (QWs) grown on GaInAs or quasi-GaInAs substrates is investigated by using microscopic many-body theory. The effects of various parameters, such as strain, barrier height, substrate composition, and temperature are thoroughly examined. It is shown that the value of the absorption coefficient strongly depends on the depth of the QWs under large bias electric field due to the small overlap integral of wave functions between the conduction and valence bands. The use of GaInNAs QWs makes the strain in the well layer very small. Further, the effective quantum-well depth is increased in GaInNAs QWs due to the anticrossing interaction between the conduction and N-resonant bands, making it possible to obtain larger absorption coefficient under large bias electric fields without using wide-band gap materials for barriers.

Material Gain Analysis of GeSn/SiGeSn Quantum Wells for Mid-Infrared Si-Based Light Sources Based on Many-Body Theory

“…Although FCT is easy to use for obtaining optical properties of QWs, it needs an experimental fitting parameter (relaxation time) associated with optical spectrum broadening originating from scattering phenomena in semiconductors. Results obtained by FCT are greatly affected by the fitting parameter (shown later), and it was demonstrated that spectral positions and the spectral shapes obtained by FCT are not consistent with the experiment [10][11][12][13][14]. Therefore, it is difficult to grasp the inherent optical properties of GeSn QWs if FCT is used for the analysis.…”

“…In this paper, the material gain of GeSn/SiGeSn QWs is investigated for mid-IR Si-photonics light sources by using microscopic many-body theory (MBT) [10][11][12][13][14][15]. MBT does not need any fitting parameters used in FCT to obtain optical properties of QWs and only needs basic bulk band parameters.…”

Quantum-Confined Stark Effect Analysis of GeSn/SiGeSn Quantum Wells for Mid-Infrared Si-Based Electroabsorption Devices Based on Many-Body Theory

“…To enhance the QCSE, it is important to use deep well (large band offset), especially for conduction band. A deep well makes the confinement of electron and hole stronger, leading to larger absorption even when the electric field is applied [15]. Therefore, to design the GeSn/SiGeSn QWs for EAM, the QW structure having large band offset has to be investigated first to use QCSE effectively.…”