Influence of strains on the structural and optical properties of nanoheterostructures with quantum island arrays and quantum wells based on group IV elements Ge, Si and Sn

At present, photodetectors, light-emitting diodes and lasers with optical pumping have been realized using GeSn and GeSiSn compounds. The Sn addition in Ge or GeSi matrix can result in direct bandgap materials, which could be... [ view full abstract ]

At present, photodetectors, light-emitting diodes and lasers with optical pumping have been realized using GeSn and GeSiSn compounds. The Sn addition in Ge or GeSi matrix can result in direct bandgap materials, which could be applied in Si photonics, plasmonics and microelectronics.

The multilayer periodic structures with the GeSiSn/Si, GeSiSn/Ge heterojunctions, including the quantum island arrays and quantum wells, were grown. The method of the control for the 2D-3D transition and superstructures was the reflection high-energy electron diffraction (RHEED). The study of strains, the content and heterointerfaces was performed by the X-ray diffraction.The sample optical properties were studied by photoluminescence (PL) spectroscopy.

We present our studies on the initial stages of the Ge_1-x-ySi_xSn_y film growth on the Ge and Si substrates and discuss the data on the structural properties of multilayer structures with the Ge_1-x-ySi_xSn_y/Ge and Ge_1-x-ySi_xSn_y/Si heterojunctions. The phase diagrams for the Sn deposition on Si(100) at room temperature and 200 °C are demonstrated in figure 1. The (7×1), (8×1) and (10×1) superstructures were first obtained on the Sn surface. New results on the appearance of Sn superstructures on Si(100) and Ge(100) templates were obtained, which allow controlling the Sn segregation phenomenon during the Ge_1-x-ySi_xSn_y/Si and Ge_1-x-ySi_xSn_y/Ge heterostructure growth. The rocking curves obtained by the X-ray diffraction from the multilayer structures containing the GeSiSn layers with the Sn content up to 14 % on the Ge and Si substrates demonstrate the pseudomorphic GeSiSn film state, sharp interfaces, as well as the conservation of the periodicity and content in all periods. The photoluminescence in mid-infrared region for the multilayer periodic GeSiSn/Si structures was detected. The blue shift with the excitation power increase is observed suggesting the presence of a type II heterostructure. It is possible to achieve a direct-band gap material replacing the Si substrate by the Ge substrate.