In this work, the double cell electrochemical etching technique is employed to study the evolution of surface morphology during the etching of p-type gallium arsenide (GaAs) in a HF:C₂H₅OH electrolyte solution. It is observed that arsenic trioxide (As₂O₃) and gallium oxide (Ga₂O₃) micron-sized transparent oxide structures grow on the GaAs surface under certain etching conditions. At a large enough current density, a continuous array of As₂O₃ microcrystals on GaAs substrate is formed. On the other hand, prolonged etching time enables formation of an oxide layer with drastically enhanced content of the Ga₂O₃ phase which is known to be a good dielectric with a wide band gap. The chemical and morphological variation from microcrystals to micro-rods is explained in terms of anodic dissolution and the oxidation process of GaAs substrates. The formed oxide species on GaAs surface can provide a good opportunity to create oxide/GaAs hetero-structures with heterojunctions for optoelectronic applications. The visible range photoluminescence (PL) properties of these micro-structures are also investigated. As₂O₃ and Ga₂O₃ micro-structures have strong PL peaks at 520 and 480 nm, respectively. Finally, the recombination lifetimes of the charge transitions are examined and discussed in the context of the underlying recombination mechanisms. These results could initiate new perspectives for As₂O₃ and Ga₂O₃ micro-structures to be employed in high-performance optoelectronic devices.

Graphical abstract

中文翻译：

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p型砷化镓上微尺度As2O3和Ga2O3氧化物结构的可控电化学生长

_{在这项工作中，采用双电池电化学蚀刻技术来研究在 HF:C 2} H ₅ OH 电解质溶液中蚀刻 p 型砷化镓 (GaAs) 过程中表面形貌的演变。观察到三氧化二砷（As ₂ O ₃）和氧化镓（Ga ₂ O ₃）微米级透明氧化物结构在特定蚀刻条件下生长在GaAs表面上。在足够大的电流密度下，在GaAs衬底上形成连续的As ₂ O _{3微晶阵列。}另一方面，延长蚀刻时间能够形成Ga ₂ O含量显着增加的氧化物层。₃相，它被认为是具有宽带隙的良好电介质。从微晶到微棒的化学和形态变化用 GaAs 衬底的阳极溶解和氧化过程来解释。GaAs 表面上形成的氧化物物质可以提供一个很好的机会来创建用于光电应用的具有异质结的氧化物/GaAs 异质结构。还研究了这些微结构的可见光范围光致发光 (PL) 特性。As ₂ O ₃和 Ga ₂ O ₃微结构分别在 520 和 480 nm 处具有强 PL 峰。最后，在潜在的复合机制的背景下检查和讨论了电荷跃迁的复合寿命。这些结果可以为 As ₂ O ₃和 Ga ₂ O ₃ 微结构用于高性能光电器件开辟新的前景。

图形概要