Monocrystalline alloys of GaAs and Ge with compositions (GaAs)yGe5–2y have been synthesized following a chemical vapor deposition approach that promotes the incorporation of Ga and As atoms as isolated donor-acceptor pairs. The structural and optical properties show distinct behavior relative to (GaAs)1-xGe2x counterparts produced by conventional routes. Strong band gap photoluminescence is observed in the 0.5–0.6 eV range for samples whose compositions approach the GaAsGe3 limit for isolated Ga-As pairs. In such samples, the Ge-like Raman modes appear at higher frequencies and are considerably narrower than those observed in samples with higher Ge concentrations. These results suggest that the growth mechanism may favor the formation of ordered phases comprising Ga-As-Ge3 tetrahedra. In contrast with the diamond-to-zincblende ordering transition previously reported for III-V-IV alloys, ordered structures built from Ga-As-Ge3 tetrahedra feature III-III and V-V pairs as third-nearest neighbors, and therefo...

中文翻译：

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由分子构建块组装的 (GaAs)yGe5-2y 合金的合成和光学性能

GaAs 和 Ge 的单晶合金具有 (GaAs)yGe5-2y 成分，是按照化学气相沉积方法合成的，该方法促进了 Ga 和 As 原子作为孤立的施主-受主对的结合。结构和光学特性显示出相对于传统路线生产的 (GaAs)1-xGe2x 对应物的不同行为。对于成分接近孤立 Ga-As 对的 GaAsGe3 极限的样品，在 0.5-0.6 eV 范围内观察到强带隙光致发光。在这些样品中，类锗拉曼模式出现在更高的频率，并且比在具有较高 Ge 浓度的样品中观察到的模式要窄得多。这些结果表明生长机制可能有利于形成包含 Ga-As-Ge3 四面体的有序相。