Study on crystallographic and electronic structure of micrometre-scale ZnO and ZnO:B rods via X-ray absorption fine-structure spectroscopy

Abstract

X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectra were recorded to investigate the electronic structure and local crystal structure of ZnO and ZnO:B powders produced via hydrothermal synthesis. ZnO and ZnO:B grow as micrometre-scale rods with hexagonal shape, as confirmed by scanning electron microscopy micrographs. The number of broken ZnO:B rods increases with increasing B concentration, as observed in the images, due to B atoms locating in between the Zn and O atoms which weakens and/or breaks the Zn–O bonds. However, no disorder within the crystallographic structure of ZnO upon B doping is observed from X-ray diffraction results, which were supported by EXAFS results. To determine the atomic locations of boron atoms in the crystal structure and their influence on the zinc atoms, EXAFS data were fitted with calculated spectra using the crystal structure parameters obtained from the crystallographic analysis of the samples. EXAFS data fitting and complementary k-weight analysis revealed the positions of the B atoms – their positions were determined to be in between the Zn and O atoms.

Insight into the Growth Mechanism and Photocatalytic Behavior of Tubular Hierarchical ZnO Structures: An Integrated Experimental and Theoretical Approach

“…18−20 There are few studies on the electronic structural properties of differently prepared ZnO particles determined by the extended X-ray absorption fine structure (EXAFS) analysis. 21,22 Therefore, for highly technical, biomedical, or photocatalytic applications, the development of a size-and morphology-controlled ZnO synthesis route is of utmost importance. In particular, S ̌aricá nd co-workers 23−27 have reported in several recent papers a strong influence of the synthesis route on the formation of ZnO particles, their size, and geometrical shape.…”

Electronic Structure Optimization of PdZn-Graphitic Carbon Nitride Nanocomposites as Electrocatalysts for Selective CO2 to CO Conversion

“… 28 Figure 2 c,d shows two characteristic peaks from metallic Pd at around 24 360 and 24 383 eV, 29 while metallic zinc showed a peak at 9662 eV. 30 Slight decreases in peak intensities were observed in the spectrum of PdZnGCN due to interactions between PdZn and g-C 3 N 4 . These interactions are critical for enhancing charge migration in the PdZnGCN composite and improving the catalytic activity and stability.…”

Solution-Processable Growth and Characterization of Dandelion-like ZnO:B Microflower Structures

“…When this growth progresses towards the formation of the same type of crystal faces, they form a free surface. This mode of growth represents a choice of orientation and leads to competitive growth [21][22][23][24][25][26][27][28]. The preferred orientation for ZnO micro-scale rods is (002), along the c-axis.…”

“…Researchers have intensively studied ZnO thin films and powders, including those doped with Cr, Mn, Fe, Co, Ni, Cu, Al, Ga, Cd, In, B, and N. The purpose of the dopant is to improve the structural, optical, and electrical properties of ZnO, and to adjust the band gap and super-cage-nano heterostructures with less cage mismatch [7,8,[10][11][12][13][14][15][16][17][21][22][23][24][25][26]. Devices based on ZnO nanostructures are alternatives to Group III-V semiconductor compounds such as GaN-, and GaAs-based devices.…”