ZnO–SiO2 nanocomposite thin films were prepared using the target-attached RF sputteringmethod without substrate heating. The PL measurements showed that theSiO2 films containing uniformly dispersed ZnO nanoparticles emit white light consisting of violet, blue, andgreen–yellow band emissions. The presence of the blue emission is attributed to the large number ofZnO/SiO2 interfaces, which enlarges the depletion layer width and then enhances the relatedtransition. The Gaussian curve fitting of PL spectra revealed that the competition betweenthe blue and green–yellow band emissions and the relative emission intensityis strongly associated with the number of ZnO nanoparticles embedded in theSiO2 matrix. XPS analysis revealed that the main component of theoxygen defect species in the ZnO nanocomposite thin films is‘O−’ ions (531.1–531.7 eV) at the subsurface. Within the knowledge of the defect configuration,XPS data were also utilized to estimate the oxygen vacancies and the specific carrierconcentration in ZnO nanoparticles and relate to the integrated intensities ofemission bands. Further analyses indicated that the defect structure of samplescould be manipulated by the number and distribution of ZnO nanoparticles inSiO2 matrix to yield a distinct luminescence spectrum.