1：Experimental Design and Method Selection:

The sol–gel method was used to prepare MgxZn1(cid:2)xO films with different x on quartz substrate. The properties of the films were characterized by SEM, XRD, Raman spectroscopy, and UV–Vis–NIR spectroscopy.

2：Sample Selection and Data Sources:

MgxZn1(cid:2)xO films with x =

3：05, 10, 15, and 20 were prepared. List of Experimental Equipment and Materials:

ZEISS Sigma HD scanning electron microscope, Rigaku IV x-ray diffractometer, WITec alpha300 RA Raman spectrometer, Cary 5000 UV–Vis–NIR spectrophotometer.

4：Experimental Procedures and Operational Workflow:

The solution was prepared by dissolving zinc acetate 2-hydrate and magnesium acetate 4-hydrate in 2-methoxyethanol and ethanol amine. The mixture was stirred at 60°C for 2 h and conserved steadily for 48 h to form a stable solution. The solution was spin-coated onto plasma-treated quartz substrates at a speed of 2500 rpm for 30 s. After the spin coating, the film was heated at 180°C to volatilize the solvent. The films were then annealed at 700°C in an oxygen atmosphere for 2 h.

5：Data Analysis Methods:

The optical bandgap energies of the MgxZn1(cid:2)xO films were determined by plotting the (ahm)2 as a function of (hm) and linearly extrapolating to (ahm)2= 0.