1：Experimental Design and Method Selection

The study involves the fabrication of porous silicon (PS) layers on n+p wafers using electrochemical etching and covering them with Al-doped ZnO (AZO) films prepared by sol–gel spin-coating method. The structural and optical properties of PS, AZO, and AZO/PS layers are investigated.

2：Sample Selection and Data Sources

n+p CZ–Si (100) wafers with a resistivity of 4–10 ? cm and a thickness of 450 μm were used. PS layers were fabricated with etching times of 15 and 25 min.

3：List of Experimental Equipment and Materials

Electrochemical etching setup, sol–gel spin-coating system, X-ray diffractometer (Bruker D8), field emission electron microscopy (FESEM, Model Quanta 250 FEG), high-resolution transmission electron microscopy (HRTEM, Joel JEM 2100), spectrometer (JASCO V570, UV–Vis–NIR), photoluminescence spectra recorder (JASCO FP-6500), Keithley 2635 A source-meter.

4：Experimental Procedures and Operational Workflow

PS layers were fabricated using electrochemical etching with HF and isopropanol. AZO films were prepared by sol–gel method and deposited on PS layers. The samples were characterized using XRD, SEM, TEM, optical spectroscopy, and photoluminescence. The solar cells' performance was evaluated under illumination.

5：Data Analysis Methods

The optical properties were analyzed using transmittance and reflectance measurements. The structural properties were analyzed using XRD and electron microscopy. The solar cells' performance was evaluated based on current density–voltage (J–V) characteristics.