Optical properties of ZnO and ZnO:In nanorods assembled by sol-gel method

Abstract

Self-assembled zinc oxide (ZnO) and indium-doping zinc oxide (ZnO:In) nanorod thin films were synthesized on quartz substrates without catalyst in aqueous solution by sol-gel method. The samples were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), Raman-scattering spectroscopy, room-temperature photoluminescence (PL) spectra, and temperature-dependent PL spectra measurements. XRD and Raman spectra illustrated that there were no single In2O3 phase in ZnO lattice after indium doping. The PL spectra of ZnO showed a strong UV emission band located at 394 nm and a very weak visible emission associated with deep-level defects. Indium incorporation induced the shift of optical band gap, quenching of the near-band-edge photoluminescence and enhanced LO mode multiphonon resonant Raman scattering in ZnO crystals at different temperatures. Abnormal temperature dependence of UV emission integrated intensity of ZnO and ZnO:In samples is observed. The local state emission peak of ZnO:In samples at 3.37 eV is observed in low-temperature PL spectra. The near-band-edge emission peak at room temperature was a mixture of excitons and impurity-related transitions for both of two samples.

Substrate temperature dependence of growth mode, microstructure and optical properties of highly oriented zinc oxide films deposited by reactive sputtering

“…The broad peak ∼ 570 cm − 1 is assigned to a combination of A 1 (LO) and E 1 (LO) modes, which are reported at 574 cm − 1 and 583 cm − 1 , respectively [30,31]. These features of Raman spectra of ZnO films are indicative of poor crystallinity, arising from lattice strain, structural defects and disorder [32][33][34]. These observations, especially the presence of weak E 2 -high mode as a shoulder, indicate that though most of the films deposited below 300°C showed [13] a single and intense (0002) peak, indicating c-axis preferred orientation of crystallites, these films actually possess poor crystalline quality.…”

Doping Induced Tailoring in the Morphology, Band-Gap and Ferromagnetic Properties of Biocompatible ZnO Nanowires, Nanorods and Nanoparticles

“…The pure ZnO has two emission peaks in UV (380 nm) and visible luminescence (VL) (524 nm) regions of the spectrum. The peak in UV is attributed to near band edge (NBE) transition due to interaction of exciton-exciton through collision process, while in VL usually called green emission band is assigned to the defects (such as singly ionized oxygen vacancy and Zn interstitial defects) [26,27]. The results for Fe doping demonstrate that the NBE and VL are strongly influenced from the amount of Fe doping as shown in Fig.…”

Effect of Ce doping on the structural, optical and magnetic properties of ZnO nanoparticles

“…The PL spectra of ZnO nanoparticles contain two strong emission peaks at UV (388.4 nm) and visible range (535 nm). The UV emission is due to the near bend-edge (NBE) emission of ZnO, which generates from the recombination of exciton-exciton through collision process [32]. The emission in the visible range is referred to as a green emission, which is the emission outcome from the radiative recombination of a photogenerated hole with an electron occupying the oxygen vacancy.…”