This dataset contains the detailed methodology for synthesizing AlₓGa₁₋ₓAs nanowires on mono-GaAs substrates via electrochemical deposition. The document outlines preparation procedures for substrates, conditions for electrochemical etching, deposition processes, and subsequent structural characterization methods. File 1 (Synthesis_AlGaAs.pdf): Describes step-by-step experimental protocols, including substrate preparation, electrolyte composition, deposition cycles, and analysis techniques such as SEM, EDX, and XRD. The dataset serves as a reference for researchers aiming to replicate or adapt the synthesis methodology for semiconductor heterostructures. Methodology: Material: AlₓGa₁₋ₓAs nanowires on mono-GaAs substrates. Substrate Preparation: Mono-GaAs wafers (n-type, Sb-doped, orientation (111)) etched in an HCl:H₂O (1:5) solution. Electrochemical Etching: Performed in HCl:H₂O (1:4) under constant voltage (5V) for 7 minutes. Electrolyte Composition: AlCl₃ solution (2:3 by mass, dissolved at 25°C and stirred for 10 minutes). Electrochemical Deposition: Three-electrode configuration (Pt as the counter electrode, Ag/AgCl as the reference electrode). Cyclic deposition: 3 cycles with 2 minutes at 3V and 1 minute at 6V. Final Treatment: Samples stabilized in the electrolyte without applied potential for 3 minutes and dried under a nitrogen stream. Analysis Techniques: SEM (morphology analysis), EDX (elemental mapping and quantitative composition analysis), and XRD (crystallographic structure analysis). File 1 (Synthesis_AlGaAs.pdf): Document detailing: Substrate preparation and etching processes. Electrolyte composition and preparation. Electrochemical deposition protocols (parameters and cycles). Characterization methodologies (SEM, EDX, XRD). Software for Data Processing: INCA Software (Oxford Instruments): EDX analysis OriginLab: Data plotting and analysis ImageJ: Image processing and analysisFunding: Supported by the National Research Foundation of Ukraine, Project No. 0124U002023 “Design and research of oxide heterostructures for portable solar cells.”