Features of Optical Transitions in GeSiSn/Si Multiple Quantum Wells

• Published in: Optoelectronics, instrumentation, and data processing instrumentation, and data processing, 2022-12, Vol.58 (6), p.571-578
• Main Authors: Timofeev, V. A., Mashanov, V. I., Nikiforov, A. I., Skvortsov, I. V., Loshkarev, I. D., Kolyada, D. V., Firsov, D. D., Komkov, O. S.
• Format: Article
• Language: English
• Subjects: Lasers; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy
• ISSN: 8756-6990; 1934-7944
• DOI: 10.3103/S8756699022060127

Interband photoluminescence was obtained for structures with multiple quantum wells (MQWs) with different content of germanium and tin. Peak position in photoluminescence spectra obtained from the MQW of Ge Si Sn /Si shifts to the long wavelength region with an increase in the Ge content in the solid solution and is observed in the energy range 0.85-0.68 eV for the germanium content from 30 to 78 . Thus, the shift of the peak along the wavelength was observed from 1.46 to 1.82 m, and the total spectral range of MQW luminescence covered by these structures was 1.3–2.1 m. An even more significant shift of the MQW photoluminescence peak to the long-wavelength region was achieved by increasing the tin content. Increasing the fraction of Sn from 7 to 14 while keeping the 30 Ge fraction constant led to a shift of the peak from 0.85 to 0.75 eV. A simultaneous increase in the content of both tin and germanium in the solid solution (up to 14 and 79%, respectively) made it possible to obtain a photoluminescence peak with an energy of 0.58 eV, which corresponds to the radiation wavelength of 2.14 m. A sharp ‘‘red’’ shift in the position of the photoluminescence peak with increasing temperature was discovered and its value reached 50 meV when the sample heating temperature was changed from 11 to 60–80 K. Such a significant shift in the position of the MQW photoluminescence peak is explained within the framework of a model that assumes that at low temperatures, charge carriers are randomly localized on spatial inhomogeneities of the MQW, and as the temperature increases, they are redistributed and transition to a thermodynamically equilibrium state with the lowest energy.