Comparison of high-resistivity ZnO films sputtered on different substrates

Abstract

The structural and electrical properties of (002)-oriented high-resistivity ZnO films with luminescent peaks ranging from 3 80 nm to 415 nm grown on SiO2/Si, Si and Coming 7059 glass substrates by radio-frequency magnetron-assisted sputtering are determined. The X-ray diffraction results reveal that the ZnO/glass sample has a narrow normalized intensity of full-width at half maximum (FWHM) compared to other samples. The photoluminescence spectra show that the band-gap energy of the ZnO/glass sample is similar to that of the ZnO bulk standard; however, a smaller band-gap energy of 2.987 eV of the ZnO/SiO2/Si sample due to the defect-induced lattice expansion effect is observed. The ZnO/glass sample has better crystallinity, but exhibits lower contact resistance and sheet resistance. In particular, the metal-semiconductor-metal diode fabricated on the ZnO/Si sample is found to exhibit a relatively larger contact resistance, sheet resistance, and specific contact resistivity of 1.02 x 10(9) Omega, 3.8 x 10(10) Omega/square, and 1.54 x 10(3) Omega-cm(2), respectively.