Germanium Laser for Silicon Photonics

• Applicants: Professor Dr. Martin Kittler; Dr.-Ing. Michael Oehme
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2013 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 236367859

Silicon-based photonics developed rapidly in the past decade, driven mainly by the ability to integrate increasingly complex optical functions on silicon wafers. Presently, manufacturing of an integrated light source is the greatest challenge for materials science. The goal of this research project is to demonstrate an electrically pumped laser, which uses the direct radiative transition in Ge. The design of that laser must allow an easy integration within the current silicon based technology. Then it can find application as an on-chip light emitter for the integrated CMOS photonics. The objectives of the current research project are:1.) Improvement of the understanding of the physical processes governing the excitation of direct Ge-luminescence as basis for optimization of the laser structure. The role of crystal defects (dislocations), mechanical strain, and dopant concentration in Ge layers on Si will be investigated in detail and compared with the bulk Ge reference.2) Investigation and optimization of active Si / Ge heterostructures for achieving maximal light emission in a vertical or a lateral LED configuration. Thereby, a defined adjustment of the elastic tension in the heterostructures will be possible during the MBE deposition on virtual substrates.3.) Implementation and development of a Ge laser integrated on Si, for which the Si / Ge heterostructures will be placed in an optical cavity with a proper lateral and vertical design in order to obtain stimulated emission.

• DFG Programme: Research Grants