1,721,181 research outputs found
Strong coupling in metal-semiconductor microcavities featuring Ge quantum wells: a perspective study
Full text linkIn this work we theoretically investigate the possibility of observing strong coupling at mid-infrared frequencies within the group-IV semiconductor material platform. Our results show that the strong coupling condition is attainable in Ge/SiGe quantum wells integrated in hybrid metal-semiconductor microcavities, featuring a highly n-doped SiGe layer as one of the mirrors
Modeling of second harmonic generation in hole-doped silicon-germanium quantum wells for mid-infrared sensing
Full text linkThe development of Ge and SiGe chemical vapor deposition techniques on silicon wafers has enabled the integration of multi-quantum well structures in silicon photonics chips for nonlinear optics with potential applications to integrated nonlinear optics, however research has focused up to now on undoped quantum wells and interband optical excitations. In this work, we present model calculations for the giant nonlinear coefficients provided by intersubband transitions in hole-doped Ge/SiGe and Si/SiGe multi-quantum wells. We employ a valence band-structure model for Si1-xGex to calculate the confined hole states of asymmetric-coupled quantum wells for second-harmonic generation in the mid-infrared. We calculate the nonlinear emission spectra from the second-order susceptibility tensor, including the particular vertical emission spectra of valence-band quantum wells. Two possible nonlinear mid-infrared sensor architectures, one based on waveguides and another based on metasurfaces, are described as perspective application
Ge/SiGe quantum well for photonic applications: Modelling of the quantum confined Stark effect
No full textGe quantum wells are emerging as a relevant material system for enabling fast and power-efficient optical modulation in the framework of Si-photonics. The need for reliable designs of QW structures, matching given operating wavelengths and bias voltages, calls for the implementation of modelling tools capturing the optical properties of SiGe heterostructures. Here we report on the calculation of the quantum confined Stark effect based on an eight-band kÃp model. The obtained spectra are analysed and compared with experimental data showing a good agreement between calculation and measurements
Strong coupling between photonic modes of stripe microcavities and intersubband transitions in Ge/SiGe multiple quantum wells
No full textIn this work, we assessed by means of numerical simulations the observability of mid-infrared intersubband polaritons in hole-doped Ge/SiGe multiple quantum wells embedded into stripe microcavities consisting of an upper gold grating and a bottom highly n-doped SiGe mirror
Determining the directional strain shift coefficients for tensile Ge: A combined x-ray diffraction and Raman spectroscopy study
Full text linkIn this work the calibration of the directional Raman strain shift coefficient for tensile strained Ge microstructures is reported. The strain shift coefficient is retrieved from micro-Raman spectroscopy measurements in combination with absolute strain measurements from x-ray diffraction using focused synchrotron radiation. The results are used to fit the phonon deformation potentials. A linear dependence of the phonon deformation potentials p and q is revealed. The method can be extended to provide strain calibration of Raman experiments also in other material system
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