Abstract The photoluminescence (PL) and PL excitation (PLE) spectra of CdTe/ZnTe asymmetric double quantum well (QW) structures are studied on a series of samples containing two CdTe layers with nominal thicknesses of 2 and 4 monolayers (ML) in the ZnTe matrix. The samples differ in the thickness of the ZnTe spacer between CdTe QWs which is 45, 65 and 75 ML. It has been found that at above-barrier excitation the PL from a shallow QW at sufficiently weak excitation intensities is determined by recombination of hot excitons. It is shown that under these conditions, when PL is excited by lasers with different wavelengths, the ratio of the PL intensities from shallow and deep QWs decreases exponentially with an increase of the initial kinetic energy of hot excitons. It is found that energy relaxation of hot excitons with LO phonon emission determine the shape of the PLE spectrum of shallow QW in the range of exciton kinetic energies up to more than 20 LO phonons above ZnTe bandgap. We have shown that the results obtained are well described by the model of charge and energy transfer between QWs.

中文翻译：

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耦合超薄 CdTe/ZnTe 量子阱结构中的热激子弛豫

摘要 在一系列样品上研究了 CdTe/ZnTe 非对称双量子阱 (QW) 结构的光致发光 (PL) 和 PL 激发 (PLE) 光谱，这些样品在 ZnTe 中包含两个标称厚度为 2 和 4 个单层 (ML) 的 CdTe 层。矩阵。样品的不同之处在于 CdTe QW 之间的 ZnTe 隔离物的厚度为 45、65 和 75 ML。已经发现，在势垒以上激发时，来自浅QW的PL在足够弱的激发强度下由热激子的重组决​​定。结果表明，在这些条件下，当 PL 被不同波长的激光激发时，浅、深 QW 的 PL 强度比随着热激子初始动能的增加呈指数下降。发现具有 LO 声子发射的热激子的能量弛豫决定了浅 QW 的 PLE 谱的形状，在激子动能范围内高达 20 多个 LO 声子高于 ZnTe 带隙。我们已经表明，QW 之间的电荷和能量转移模型很好地描述了获得的结果。