Abstract

Based on calculations within the density functional theory and an analysis of low-temperature photoluminescence spectra, the structure of electron–hole liquid in shallow Si/Si_1 – xGe_xSi (100) quantum wells 5 nm wide with germanium content x = 3–5.5% is studied. It is shown that the energy of quasi-two-dimensional electron–hole liquid localized in quantum wells for this composition range as a function of carrier concentration exhibits two local minima. The position of the deeper (major) minimum depends on the quantum well design and controls properties of quasi-two-dimensional electron–hole liquid at low temperatures. For the series of Si/Si_1 – xGe_xSi quantum wells, modification of properties of electron–hole liquid was experimentally shown, which can be interpreted as a change of the major minimum due to an increases in the germanium concentration in the Si_1 – xGe_x layer. The effect of the multicomponent composition (electrons, light and heavy holes) of the electron–hole liquid on low-temperature photoluminescence spectra of Si/Si_1 ‒ xGe_xSi quantum wells is discussed.

中文翻译：

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浅Si / Si 1 – x Ge x Si量子阱中两种电子空穴液体的发射光谱和稳定性

摘要

基于密度泛函理论中的计算和对低温光致发光光谱的分析，浅的Si / Si _{1 –  x} Ge _x Si（100）量子阱中5纳米宽，锗含量x = 3的电子-空穴液体的结构–5.5％被研究。结果表明，在此量子阱中，准二维电子空穴液体的能量随载​​流子浓度的变化呈现出两个局部最小值。最小（主要）最小值的位置取决于量子阱的设计，并控制低温下准二维电子空穴液体的性质。对于Si / Si _{1 –  x} Ge _x系列硅量子阱，通过实验显示了电子空穴液体性质的改变，这可以解释为由于Si _{1 –  x} Ge _x层中锗浓度增加而导致的最小最小值的变化。讨论了电子空穴液体的多组分组成（电子，轻空穴和重空穴）对Si / Si _{1  x} Ge _x Si量子阱的低温光致发光光谱的影响。