Growth of transparent Zn1 − xSrxO (0.0 ≤ x ≤ 0.08) films by facile wet chemical method: Effect of Sr doping on the structural, optical and sensing properties

Abstract

Zn1−xSrxO (0.0≤x≤0.08) nano-rods thin films are prepared using simple wet chemical technique on transparent flexible substrate. Effect of Sr-doping on structural and optical properties of ZnO is systematically investigated. SEM and TEM confirm the nano-rods like morphology with single crystalline nature of all the samples. Rietveld refinement of XRD shows the samples belongs to P63mc space group, furthermore, a gradual increment in lattice parameters and change in Zn/oxygen occupancy ratio is observed with Sr doping. SIMS and XPS confirm the doping of Sr in the ZnO nanostructures. XPS measurements shows that increase in Sr doping creates more oxygen associated defects, which is further supported by the photoluminescence spectra indicating the gradual change in Zn vacancy (Vzn) and oxygen interstitial (Oin) point defect intensities in the films. Near band edge emission peak shows to shift toward higher wavelength in the doped films. Pure ZnO film shows Raman peaks around 99(E2low), 333(E2high−E2low), 382 (A1 (TO)), 438(E2high) and 582 (A1 (LO) +E1 (TO)) cm−1, whereas two additional defect driven vibrational modes (at 277 and 663cm−1) are appeared in the Sr-doped films. The sensing property of the ZnO is enhanced by Sr doping and replicates as a promising material for future toxic and flammable gas sensor applications as well as for opto-electronic devices.