Abstract High-crystalline quality CdTe thin films are grown on the largely lattice-mismatched SrTiO 3 (STO) (1 1 1) substrates by molecular beam epitaxy. A transformation from a three dimensional regime to a two dimensional one is observed by the reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM). The formation of an elastic deformation CdTe layer on STO (1 1 1), namely a pseudomorphic growth mode with a critical thickness of ∼40 nm, is supported by the RHEED, AFM and X-ray diffraction. Crystal structures and epitaxial relationships of CdTe epitaxial films on STO (1 1 1) are characterized by 2 θ - ω scans and reciprocal space mapping. Two strong absorption peaks at the energies of ∼1.621 eV and ∼1.597 eV at 5 K are clearly observed for a ∼120 nm thick CdTe epitaxial film, which are proposed to be ascribed to the strained and unstrained epitaxial CdTe layers, respectively. Moreover, the presence of the exciton band while the absence of deep level defect states for the ∼120 nm thick CdTe film characterized by the temperature dependent photoluminescence spectra further supports the high-crystalline quality.

中文翻译：

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钙钛矿 SrTiO 3 (111) 衬底上高质量闪锌矿 CdTe 薄膜的分子束外延生长、透射率和光致发光光谱

摘要 通过分子束外延在晶格失配的 SrTiO 3 (STO) (1 1 1) 衬底上生长高结晶质量的 CdTe 薄膜。通过反射高能电子衍射 (RHEED) 和原子力显微镜 (AFM) 观察到从三维状态到二维状态的转变。RHEED、AFM 和 X 射线衍射支持在 STO (1 1 1) 上形成弹性变形 CdTe 层，即临界厚度约为 40 nm 的假晶生长模式。STO (1 1 1) 上 CdTe 外延膜的晶体结构和外延关系的特征在于 2 θ - ω 扫描和倒易空间映射。对于约 120 nm 厚的 CdTe 外延膜，可以清楚地观察到在 5 K 时能量为 ~1.621 eV 和 ~1.597 eV 的两个强吸收峰，建议分别归因于应变和非应变外延 CdTe 层。此外，以温度相关的光致发光光谱为特征的~120 nm厚的CdTe膜的激子带的存在而没有深能级缺陷状态进一步支持了高结晶质量。