1：Experimental Design and Method Selection:

The study involved synthesizing strongly textured bulk polycrystals of various ZnO-based natural superlattices (In2O3(ZnO)k, InFeO3(ZnO)4, InGaO3(ZnO)4, Ga2O3(ZnO)k) with high phase purity. Characterization and measurements were performed for both in-plane and cross-sectional directions to reveal anisotropic transport properties. First-principles calculations were used for phonon transport properties of InGaO3(ZnO)

2：Sample Selection and Data Sources:

Samples were synthesized using a wet chemistry sol-gel method with precursor powders, sintered via spark plasma sintering, and annealed to achieve single-phase purity. Data were obtained from XRD, SEM, HRTEM, UV-VIS-NIR spectrophotometry, thermal diffusivity, electrical conductivity, Seebeck coefficient, and Hall measurements.

3：List of Experimental Equipment and Materials:

Equipment includes spark plasma sintering system (LABOX-325, Sinter Land?), XRD (Rigaku D/Max 2500 PC), FE-SEM (Zeiss? Supra55), HRTEM (JEOL?, JEM-2100F), UV-VIS-NIR spectrophotometer (SHIMADZU?, UV-3600 Plus), laser flash apparatus (Netzsch Micro Flash? LFA 457), electrical property measurement system (Netzsch SBA 458 Nemesis), Hall measurement system (Ecopia HMS-5500). Materials include indium nitrate, gallium nitrate, ferric nitrate, zinc acetate, oxalic acid, nitric acid.

4：0). Materials include indium nitrate, gallium nitrate, ferric nitrate, zinc acetate, oxalic acid, nitric acid. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis involved sol-gel method, calcination, sintering, annealing, and cutting samples for measurements. Characterization included XRD for phase purity and texture, SEM for microstructure, HRTEM for fine structure, optical spectroscopy for bandgap, thermal diffusivity measurements, electrical conductivity and Seebeck coefficient measurements, and Hall measurements. Computational details involved DFT calculations for phonon properties.

5：Data Analysis Methods:

Data were analyzed using orientation index for XRD, Tauc equation for bandgap, Kopp-Neumann rule for specific heat, Wiedemann-Franz law for electronic thermal conductivity, SPB model for effective electron mass, and interface energy barrier transport model for electron potential barriers. Phonon properties were calculated using PHONOPY and ShengBTE packages.