1：Experimental Design and Method Selection:

The study uses a reduced temperature of 450°C for CIGS deposition to suppress GaOx formation. Na doping is controlled via NaF post-deposition treatment (PDT) and diffusion from soda-lime glass. Various ITO back contact structures are fabricated and characterized.

2：Sample Selection and Data Sources:

Samples include CIGS solar cells with different ITO thicknesses (200 nm and 600 nm), with and without Mo or SiOx layers, and with or without NaF PDT. Data is collected from photovoltaic performance measurements, TEM, SIMS, XPS, UPS, PL, and other analyses.

3：List of Experimental Equipment and Materials:

ITO films deposited by RF magnetron sputtering, CIGS films by co-evaporation, NaF for PDT, CdS buffer by CBD, i-ZnO and AZO by RF sputtering, Ni-Al grid by e-beam evaporation. Characterization equipment includes TEM (Talos F200X), SIMS (Cameca IMS-4FE7), XPS/UPS (PHI 5000 VersaProbe), PL system with DPSS laser and monochromator, j-V measurement setup with Keithley source meter, and cryostat for temperature-dependent measurements.

4：Experimental Procedures and Operational Workflow:

ITO films are prepared on SLG or SLG/SiOx substrates. CIGS is deposited at 450°C using a modified three-stage co-evaporation process. NaF PDT is applied post-deposition. Devices are fabricated with CdS, i-ZnO, AZO, and Ni-Al grid. Performance is measured under AM 1.5 illumination. Interface structures are analyzed via TEM and EDS. Elemental and electronic properties are probed with SIMS, XPS, UPS, and PL.

5：5 illumination. Interface structures are analyzed via TEM and EDS. Elemental and electronic properties are probed with SIMS, XPS, UPS, and PL. Data Analysis Methods:

5. Data Analysis Methods: j-V curves are analyzed for photovoltaic parameters. DLCP is used for carrier density profiling. TEM and EDS provide structural and compositional data. XPS and UPS give electronic structure information. PL spectra are analyzed for defect states.