Two-Dimensional Electron-Hole Liquid in Systems of Spatially Direct and Indirect Excitons in Si/SiGe Heterostructures

The two-dimensional electron-hole liquid (EHL) in 2- and 4-nm-thick SiGe layers of Si/Si0.91Ge0.09/Si heterostructures is discovered and its properties are studied by photoluminescence (PL) spectroscopy in the near-infrared and visible spectral ranges at low temperatures. It is shown that the PL in the visible range observed at high excitation levels originates from two-electron recombination transitions in the EHL. For the SiGe layer thickness d = 2 nm, the barrier formed by this layer for electrons in the conduction band is tunnel-transparent, and the EHL is spatially direct. For d = 4 nm, this barrier is nontransparent, and the EHL has dipolar character, with holes being confined in the SiGe layer and electrons occupying Si layers. It is found that the binding energy and the critical temperature of the dipolar EHL is substantially less than the spatially direct. The binding energy of free biexcitons in the tunnel-transparent SiGe layer is determined

Four-Particle Recombination Luminescence of Electron-Hole Liquid and Biexcitons in SiGe Quasi-Ttwo-Dimensional Layers of Silicon Heterostructures in the Visible Spectrum

In this study, we investigate the energy spectrum and collective effects in the system of excitons in strained SiGe layers in a series of Si/Si1-xGex/Si heterostructures with 0.05 x 0.25 and the layer thickness d 2 5 nm. We use the low-temperature photoluminescence spectroscopy both in the near-infrared and the visible spectral regions. In the latter case, the luminescence originates from simultaneous recombination of two electrons with two holes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3487

Four-Particle Recombination Luminescence of Electron-Hole Liquid and Biexcitons in SiGe Quasi-Ttwo-Dimensional Layers of Silicon Heterostructures in the Visible Spectrum

In this study, we investigate the energy spectrum and collective effects in the system of excitons in strained SiGe layers in a series of Si/Si1-xGex/Si heterostructures with 0.05 x 0.25 and the layer thickness d 2 5 nm. We use the low-temperature photoluminescence spectroscopy both in the near-infrared and the visible spectral regions. In the latter case, the luminescence originates from simultaneous recombination of two electrons with two holes. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3487