Nanotribological behavior of thermal treatment of zinc titanate thin films

Abstract

We present a study of the nanotribological behavior of ZnTiO 3 films; the surface morphology, stoichiometry, and friction (m) were analyzed using atomic force microscopy, X-ray photoelectron spectroscopy, and nanoscratch system. It is confirmed that the measured values of H and m of the ZnTiO 3 films were in the range from 8.5 AE 0.4 to 5.6 AE 0.4 GPa and from 0.164 to 0.226, respectively. It is suggested that the hexagonal ZnTiO 3 decomposes into cubic Zn 2 TiO 4 and rutile TiO 2 based on the thermal treatment; the H, m, and R MS were changed owing to the grain growth and recovery that results in a relax crystallinity of ZnTiO 3 films. From X-ray photoelectron spectroscopy measured, core levels of O 1 can attribute the weaker bonds as well as lower resistance after thermal treatment. The XRD patterns showed that as-deposited films are mainly amorphous; however, the hexagonal ZnTiO 3 phase was observed with the ZnTiO 3 (104), (110), (116), and (214) peaks from 620 to 820 C, indicating that there is highly (104)-oriented ZnTiO 3 on the silicon substrate.

Cathodoluminescence study of defects in thermal treatment of zinc titanate thin films deposited by a cosputtering process

“…The emission is shown in the CL spectrum (Figure D) of the RT specimen, which provides a low emission in the visible range and a broad band in the red spectral range centered at 1.9 eV (650 nm). The low emission maybe can be attributed to oxygen vacancy levels or interstitial oxygen defects . Low brightness is obtained in both polychromatic imaging and monochromatic imaging (Figure B,C), which matched the trend of the response of the CL spectrum intensity.…”

“…The CL spectrum consists of 2 bands that are centered at 2.18 and 2.75 eV (Figure H). In the recent work, we found the increased intensity of the (104) orientation of ZnTiO 3 is obtained in the same samples. The preferred orientation tends to reduce its free energy to reach a stable state as well as to adjust chemical bonding states, which may be the reason for the higher emission efficiency.…”

“…A trend was noted that the RMS increased with increasing annealing temperature: at 820°C, RMS = 19.5 nm, while at 920°C, RMS = 21.6 nm. Previous reports suggest that increasing the annealing temperature enhanced the atomic mobility and caused the film recovery to result in weak mechanical properties when the films are annealed under elevated temperatures …”

“…The films were cs 220 nm in thickness. The detailed deposition conditions of the ZnTiO 3 films have been provided in previous articles …”

“…Meanwhile, single‐phase Zn 2 Ti 3 O 8 films were prepared at temperatures lower than the sintering temperature of the bulk specimen . Earlier, we have concluded that the mechanical properties of the ZnO–TiO 2 system can be changed through its microstructures, grain sizes, and morphologies . The real risks of this meta‐stability in the ZnO–TiO 2 system to its applications has not yet been discussed in the literature.…”