1：Experimental Design and Method Selection:

The CZTS thin films were prepared using RF magnetron sputtering from a single quaternary target. The RF power, in-situ substrate temperature (ISST), and post-deposition annealing temperature (PDAT) were optimized to achieve single-phase crystalline CZTS.

2：Sample Selection and Data Sources:

Silicon substrates were used for the deposition of CZTS thin films. The substrates were cleaned using a solution of 2% HF and DI water followed by ultra-sonication in acetone and dried in a hot air oven.

3：List of Experimental Equipment and Materials:

RF magnetron sputtering system (make: Edwards, capacity: 300 l/s), tubular furnace for post-annealing, X-ray diffraction (XRD), Raman spectrometer (Reinshaw inVia Raman Microscope, UK), atomic force microscope (Multimode 8, Veeco Nanoscope), scanning electron microscope (VEGA 3, TESCAN), energy dispersive analysis of x-rays (EDAX), high resolution transmission electron microscope (HR-TEM) (JEOL/JEM 2100), X-ray photoelectron spectroscopy (XPS) (PHI 5000 Versa Probe II, FEI), UV-Vis-NIR spectrophotometer (Shimadzu UV-3600 plus, Japan), Fluorescence Spectrometer (FLUOROLOG-FL3-11, Jobin Yvon, Inc), and Hall measurement system (Agilent device analyser-B1500A).

4：Experimental Procedures and Operational Workflow:

The sputtering process was carried out in Ar atmosphere with a flow rate of 25 sccm and a working pressure of ~

5：5×10-3 mbar. The deposition time was 60 minutes. After sputtering, the films were post-annealed in a tubular furnace under vacuum at 500°C for 60 minutes. Data Analysis Methods:

The crystallinity and phase formation were analyzed using XRD and Raman spectroscopy. The surface morphology was studied using AFM and SEM. The optical properties were examined using UV-Vis-NIR spectrophotometer and photoluminescence spectroscopy. The electrical properties were measured using Hall effect measurement.