Morphological and optical properties of ZnO thin films grown on Si and ITO glass substrates

Abstract

In this study, ZnO thin films have been electrodeposited from zinc nitrate solution without using any catalyst, additive or seed layer on two kinds of substrates (Si and ITO glass).Using cyclic voltammetry and chronoamperometry, it was shown that the mechanism of ZnO deposition strongly depends on the substrate used and its overpotential for nitrate reduction. On Si, the nitrate reduction into nitrite occurs before that of Zn 2+. This reaction induces an increase of the local pH leading to ZnO precipitation. In contrast on ITO, the Zn 2+ reduction brings first metallic Zn deposition, which is then chemically oxidized by nitrate into ZnO phase. The effect of deposition time on morphology, structure and photoluminescence properties was studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) measurements.The chemical nature of the substrate has no influence on the orientation of nanorods, but really impacts their morphology and the optical emission properties. X-ray diffraction analysis always revealed ZnO wurtzite phase with a (002) preferential orientation enhanced with increasing deposition time. A well-defined ZnO morphology was generated under-1.4 V for 60 min on Si and ITO glass. ZnO nanorods that composed the nanoflowers grown on ITO glass tend to be shorter, wider, with higher aspect ratio than on Si. ZnO nanostructures prepared on ITO showed an intense UV emission without spreading in the visible region, thus demonstrating the formation of a defect free structure.

Design of effective self-powered SnS2/halide perovskite photo-detection system based on triboelectric nanogenerator by regarding circuit impedance

“…the XRD characterization of electrodeposited ZnO and Cu 2 O layers on the transparent conductive oxide as the substrate shows the (100), (002), (101), (102) and (110) peaks for ZnO layer and (110), (111), (220) and (222) for Cu 2 O layer (Figs. S3 a,b), which are in accordance with the other reports, confirm the proper formation of these materials 33 , 34 . Moreover, the FESEM analysis of the ZnO deposition shows the homogenous and good coverage of the ZnO nanoparticulated films on the substrate (Fig.…”

Effects of annealing temperature on properties of InSnZnO thin film transistors prepared by Co-sputtering

“…5(a), the rst peak near 386 nm (3.2 eV) may be related to bound excitons. [18][19][20] Some researchers suggested that it is attributed to the UV emission of the radiative recombination of excitons near conduction band levels at the exciton level. 21,22 The second peak in the visible range of 413 nm (3.0 eV) is attributed to transitions from the Sn i level to VBM.…”

“…21,22 The second peak in the visible range of 413 nm (3.0 eV) is attributed to transitions from the Sn i level to VBM. 20 The third peak at about 437 nm (2.84 eV) can be attributed to the transition from Sn i to V Sn and from the zinc gap (Zn i ) to the zinc vacancy (V Zn ). [23][24][25] The fourth emission peak of the dominant PL spectrum at about 446 nm (2.78 eV) is attributed to oxygen vacancy-related defects, which results in two donor levels below the conduction band minimum of 1.3-1.6 eV and 0.3-0.5 eV.…”