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arXiv · 2101.05518

THz intersubband electroluminescence from n-type Ge/SiGe quantum cascade structures

David Stark·Muhammad Mirza·Luca Persichetti·Michele Montanari·Sergej Markmann·Mattias Beck·Thomas Grange·Stefan Birner·Michele Virgilio·Chiara Ciano·Michele Ortolani·Cedric Corley·Giovanni Capellini·Luciana Di Gaspare·Monica De Seta·Douglas J. Paul·Jérôme Faist·Giacomo Scalari
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Abstract

We report electroluminescence originating from L-valley transitions in n-type Ge/Si$_{0.15}$Ge$_{0.85}$ quantum cascade structures centered at 3.4 and 4.9 THz with a line broadening of $\Delta f/f \approx 0.2$. Three strain-compensated heterostructures, grown on a Si substrate by ultrahigh vacuum chemical vapor deposition, have been investigated. The design is based on a single quantum well active region employing a vertical optical transition and the observed spectral features are well described by non-equilibrium Green's function calculations. The presence of two peaks highlights a suboptimal injection in the upper state of the radiative transition. Comparison of the electroluminescence spectra with similar GaAs/AlGaAs structure yields one order of magnitude lower emission efficiency.

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David Stark, Muhammad Mirza, Luca Persichetti, Michele Montanari, Sergej Markmann, Mattias Beck, Thomas Grange, Stefan Birner, Michele Virgilio, Chiara Ciano, Michele Ortolani, Cedric Corley, Giovanni Capellini, Luciana Di Gaspare, Monica De Seta, Douglas J. Paul, Jérôme Faist, Giacomo Scalari. 2021-01-14. THz intersubband electroluminescence from n-type Ge/SiGe quantum cascade structures. https://doi.org/10.1063/5.0041327

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