Investigation of Ge/SiGe Quantum Well properties by room temperature photoluminescence

Mumtahina Rahman (1) , Elena Durán Valdeiglesias (1) , Vladyslav Vakarin (1) , Jacopo Frigerio (2) , Joan Manel Ramírez (1) , Daniel Chrastina (2) , Papichaya Chaisakul (1) , Xavier Le Roux (1) , Laurent Vivien (1) , Giovanni Isella (2) , Delphine Marris-Morini (1)

1 IEF - Institut d'électronique fondamentale
2 POLIMI - Politecnico di Milano [Milan]

Silicon photonics has become a mature integrated-optics technology in the last decade for applications in telecommunications and data communications. Germanium (Ge) is a group IV material compatible with CMOS foundry and interesting for silicon photonics because its direct gap energy corresponds to absorption band-edge at 1.55 µm wavelength. In addition despite being an indirect band gap material, direct gap-transitions can be used for photonic devices, thanks to the small energy difference between the indirect and direct bandgap energies. The potential of Ge/SiGe quantum wells (QW) has been largely shown recently, with for example demonstrations of electro-absorption and electro-refraction by Quantum Confined Stark effect. Ge/SiGe QW can also be engineered to shift absorption band-edge and thus the operating wavelength of optical modulator based on such structures. In this context, experimental analysis of the material properties of Ge/SiGe QW structures and particularly direct gap optical transitions is of a major importance. We will report room temperature photoluminescence of Ge/SiGe QW structures grown on SiGe graded layer. From the measurements, transition energies in the QW are deduced as a function of the QW design, and compared with simulations. A good agreement between photoluminescence measurements and simulations of the optical transitions in the QW is of a major importance to engineer new Ge/SiGe quantum well structures with innovative functionalities.

Domaines: Optique / photonique

Mumtahina Rahman, Elena Durán Valdeiglesias, Vladyslav Vakarin, Jacopo Frigerio, Joan Manel Ramírez, et al.. Investigation of Ge/SiGe Quantum Well properties by room temperature photoluminescence. E-MRS Spring Meeting,, May 2016, Lille, France. ⟨hal-01322078⟩