Abstract We present a first study of films of the quaternary Bi2−xSbxTe3−ySey solid solutions on (0 0 0 1) sapphire substrates grown by atmospheric pressure MOVPE. Trimethylbismuth, trimethylantimony, diisopropylselenide and diethyltelluride were used as precursors. To passivate the free bonds of the substrate and to improve the epitaxy, a thin (15 nm) ZnTe buffer layer was first grown. EDX analysis of the films grown at a temperature of 445 °C and about 10-fold excess of chalcogen in the vapor phase indicates on their compliance with V2VI3 stoichiometry. AFM and SEM investigations showed that at the initial stage of deposition the Stranski-Krastanov growth mode is dominant. Complete coalescence of nanoislands occurs at a thickness about 60 nm and further film formation is in the 2D layer-by-layer growth mode. A high mole fraction of antimony in the vapor phase leads to bad crystalline quality of the films and even to their discontinuity. Transport properties of the Bi2−xSbxTe3−ySey films were evaluated using Van der Pauw Hall effect measurements in the range of temperatures of 10–300 K. Some films are always n- or p-type; in other samples the change of conductivity from p- to n-type was observed when the temperature decreases.

中文翻译：

---

Bi 2-x Sb x Te 3-y Se y 薄膜的 MOVPE 生长和传输特性

摘要 我们首次对通过大气压 MOVPE 生长的 (0 0 0 1) 蓝宝石衬底上的四元 Bi2-xSbxTe3-ySey 固溶体薄膜进行了研究。三甲基铋、三甲基锑、二异丙基硒化物和二乙基碲化物用作前体。为了钝化衬底的自由键并改善外延，首先生长薄 (15 nm) ZnTe 缓冲层。在 445 °C 的温度和约 10 倍过量的气相硫属元素下生长的薄膜的 EDX 分析表明它们符合 V2VI3 化学计量。AFM 和 SEM 研究表明，在沉积的初始阶段，Stranski-Krastanov 生长模式占主导地位。纳米岛的完全聚结发生在约 60 nm 的厚度处，进一步的薄膜形成处于 2D 逐层生长模式。气相中高摩尔分数的锑导致薄膜的结晶质量差，甚至导致薄膜的不连续性。Bi2−xSbxTe3−ySey 薄膜的传输特性使用范德堡霍尔效应测量在 10-300 K 的温度范围内进行评估。一些薄膜总是 n 型或 p 型；在其他样品中，当温度降低时，观察到电导率从 p 型变为 n 型。