Design and fabrication of GeSn based components for environmental detection

Published : 8 February 2020

Integrated laser sources compatible with microelectronic technologies is currently one of the main challenges for silicon photonics. CEA is part of the few laboratory that demonstrated mid-infrared optically pumped lasing in GeSn micro-cavities. Our aim is to go towards lasing at room temperature in fully relaxed or tensile-strained heterostructures and quantum wells made of germanium tin alloys. Defect reduction in the gain zone and carrier confinement optimisation in order to reach high gain is the major issue of this study. We would indeed like to minimize the lasing threshold and obtain continuous emission lasers. We also target a decrease the concentration of tin in germanium by focusing strain to further increase the crystalline quality of quantum wells and heterostructures and still reach direct band gap in the structures. Objectives of the research will be (i) to reduce crystalline defects in the gain zone, (ii) to find efficient geometries to confine electrons and holes, (iii) to apply tensile strain to germanium tin crystals, (iv) to evaluate the electrical gain dependence with different strains and doping levels, (v) to characterise the optoelectronic properties of epitaxial materials, (vi) to design and fabricate laser cavities with strong optical confinement in order to reach tunable continuous germanium lasers compatible with the current microelectronic technologies for environmental detection.

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