Optical properties and dynamics of direct and spatially and momentum indirect excitons in AlGaAs/AlAs quantum wells

Dąbrówka Biegańska; Maciej Pieczarka; Krzysztof Ryczko; Maciej Kubisa; Sebastian Klembt; Sven Höfling; Christian Schneider; Marcin Syperek

arXiv · 2404.01938

Optical properties and dynamics of direct and spatially and momentum indirect excitons in AlGaAs/AlAs quantum wells

Dąbrówka Biegańska·Maciej Pieczarka·Krzysztof Ryczko·Maciej Kubisa·Sebastian Klembt·Sven Höfling·Christian Schneider·Marcin Syperek

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Abstract

We present an experimental study on optical properties and dynamics of direct and spatially and momentum indirect excitons in AlGaAs/AlAs quantum wells near the crossover between $\varGamma-$ and $X$-valley confined electron states. The time-integrated photoluminescence experiment at $T=$4.8 K revealed three simultaneously observed optical transitions resulting from (a) a direct exciton recombination, involving an electron and a hole states both located in the $\varGamma$-valley in the quantum well layer, and (b) two spatially and momentum indirect excitons, comprising of the confined electron states in the $X$-valley in the AlAs barrier with different effective masses and quantum well holes in the $\varGamma$-valley. This interpretation has been based on the optical pumping density-dependent, temperature-dependent and spatially-resolved photoluminescence measurements, which provided the characterization of the structure, crucial in potential system's applications. Additionally, the time-resolved photoluminescence experiments unveiled complex carrier relaxation dynamics in the investigated quantum well system, which is strongly governed by a non-radiative carrier recombination - the characteristics further critical in potential system's use. This solid state platform hosting both direct and indirect excitons in a highly tunable monolithic system can benefit and underline the operation principles of novel electronic and photonic devices.

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Dąbrówka Biegańska, Maciej Pieczarka, Krzysztof Ryczko, Maciej Kubisa, Sebastian Klembt, Sven Höfling, Christian Schneider, Marcin Syperek. 2024-04-02. Optical properties and dynamics of direct and spatially and momentum indirect excitons in AlGaAs/AlAs quantum wells. https://arxiv.org/abs/2404.01938

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