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Effect of well-width on the electro-optical properties of a quantum well

Arjun Joshua·V. Venkataraman
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Abstract

We record photoreflectance from Ge/GeSi modulation doped quantum wells possessing $10^4$ V/cm perpendicular electric fields. Qualitatively very different spectra are obtained from samples of well-width 100 Åand 250 Å. Comparing the wavefunctions calculated from an $8 \times 8$ \textbf{k.p} theory, we find that while they remain confined in the narrower 100 ÅQW, the electric field causes them to tunnel into the forbidden gap in the 250 Å well. This implies that the samples should show a transition from the quantum confined Franz-Keldysh effect to the bulk-like Franz-Keldysh effect. Close to the band-edge where Franz-Keldysh effects are important, simulated photoreflectance spectra reproduce the essential features of the experiment, without any adjustable parameters.

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Arjun Joshua, V. Venkataraman. 2004-02-25. Effect of well-width on the electro-optical properties of a quantum well. https://doi.org/10.1088/0268-1242%2F20%2F6%2F003

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