Physicochemical properties of surface chargemodified zno. From fesem studies, zno and co doped zno nps showed spherical and nanorod mixed phase and spherical like morphology, respectively. Xray diffraction xrd pattern reveals wurtzite structure of zno nanoparticles. The natural crystal structure of zno is the hexagonal wurtzite structure.
These compounds have recently received considerable attention due to their potential in the semiconductor industry. All evident peaks could be indexed as the zno wurtzite structure jcpds data card no. Pure zno and cobalt co doped zno nanoparticles nps were synthesized by the coprecipitation method. Wurtzite structure of zno nanoparticles is belonging to space group. Thus, hcp clusters can attain their preference with respect to mtps comprising fcc fragments and optimized fcc clusters only for very large sizes. The chemical prototype is conventionally given as zns, although mineral wurtzite is a multicomponent alloy compound. The two important characteristics of the wurtzite structure are the noncentral symmetry and polar surfaces. Ke1,2,a 1school of physics and nuclear energy engineering, beihang university, beijing 100191, peoples republic of china 2lnm, institute of mechanics, chinese academy of sciences, beijing 100190, peoples republic of china. The two hcp lattices have the same axis a 3 axis but one of them is displaced with respect to the other. The wurtzite structure may be considered as an hcp structure with a basis of two atoms. In the extreme case u 12 this structure becomes the b k bn structure.
Pdf firstprinciples study on zno nanoclusters with. Among the binary oxide semiconductors, zno is the only material with a wurtzitetype structure that has a. Abstract this chapter starts with an overview of the zno crystal structure and its. The wurtzite structure of zno can be considered to be composed of two. The wurtzite structure is most stable and thus most common at ambient conditions. The hole effectivemass parameters of zno wurtzite material are calculated by the empirical pseudopotential method. The zinc blend form can be stabilized by please purchase pdf split merge on. In a real zno crystal, the wurtzite structure deviates from the ideal arrangement. Draw wurtzite crystal structure with vesta zno example. In this study, four types of standardized zno nanoparticles were prepared for assessment of their potential biological risk.
Rod shape of zno nanoparticles of average particle size 10. N species concerns its exceptionally high concentration of zinc vacancies, as great as 17%, i. In addition to the nitrogen doping, the main characteristic of this zno. Rietveld refinement carried out by fullprof software of xrd patterns a provide accurate values. Phase transformation in radially merged wurtzite gaas. It has a hexagonal close packed array of s and the znii sit in tetrahedral 12 occupied sites in the lattice.
Synthesis and characterization of zno nanoparticles. Zno zinc blende unit cell the hexagonal structure of zinc oxide zno has a point group 6 mm in hermannmauguin notation or c6vin reported space group is generally p63mc or c6v4. The zinc blende zno structure is metastable and can be stabilized only by heteroepitaxial growth on cubic substrates, such as zns 5, gaaszns 6, and. Zno nps have characteristic peaks of hexagonal wurtzite zno structure. Crystal and electronic structure study of mn doped.
Its crystal structure is called the wurtzite crystal structure, to which it lends its name. The wurtzite crystal structure, named after the mineral wurtzite, is a crystal structure for various binary compounds. Multiple datasets can be downloaded as individual files inside a zip archive by selecting the datasets and then clicking. Wurtzite lattice parameters such as the values of d, the distance between adjacent planes in the miller. Wurtzitetotetragonal structure phase transformation and. Structural and optical characterization of zno nanoparticles synthesized by microemulsion route harish kumar. All the powder diffraction peaks could be indexed to the hexagonal wurtzite structure of zno, which was further confirmed from the jcpds no. The raman spectrum measurement result is comparable with that of the xrd analysis, which shows a single peak at 002 corresponding to the wurtzite structure of zno. Crystal structure, chemical binding, and lattice properties. Zno nanoparticles were synthesized by microemulsion route in ws ratio of 5 at room temperature. The structural properties of wurtzite and rocksalt mgxzn1.
Structural and optoelectronic properties of unsaturated zno and. The asprepared specimen exhibits strong ultraviolet exciton emission at 385 nm and disappearance of visible defect emission. Multiple datasets can be concatenated into a single downloadable file by selecting the datasets and then clicking. Xray peak broadening analysis of zno nanoparticles.
Compound semiconductors with zincblende or wurtzitetype structureswhere each atom of one element is in 4fold and tetrahedral coordination to atoms of the other element. This structure is a member of the hexagonal crystal system and consists of tetrahedrally coordinated zinc and sulfur atoms that are stacked in an ababababab pattern. The wurtzite structure is a hexagonal lattice in which each zn. Powderphased zno nanoparticles with different particle sizes 20 nm and 100 nm were coated with citrate or lserine to induce a.
It is found that the electron states are either twofold or fourfold degenerate. Zinc oxide zno is a wide band gap semiconductor with an energy gap of 3. To find out more, see our privacy and cookies policy. Wurtzitetotetragonal structure phase transformation and size effect in zno nanorods j. In this work, we studied the crystal structure of radially overgrown gaas wurtzite 2h nws, especially the resulting crystal structure as nws progressively grow into each other and merge. Wurtzite zinc oxide has a hexagonal structure space group c6mc with lattice. Draw wurtzite crystal structure with vesta zno example easyedu. Zno crystal has a wurtzite structure with c6v symmetry arxiv. We use cookies to offer you a better experience, personalize content, tailor advertising, provide social media features, and better understand the use of our services. Regularly shaped, singlecrystalline zno nanorods with. Electronic structures of wurtzite zno and zno mgzno.
We characterized the grown structure by high resolution xrd and tem with diffraction analysis. Xray diffraction xrd pattern refers polycrystalline nature with a hexagonal structure. Structures of wurtzite zno solid solutions with mgo and cdo by first principles calculations zhijun wang 1,2 and isao tanaka1,3 1 department of materials science and engineering, kyoto university, kyoto, 6068501, japan 2physics department, jilin university, changchun, jilin, 026, china 3 nanostructures research laboratory, japan fine ceramics center, nagoya, 4568587, japan. The wurtzite structure of zno crystal has c6v symmetry.
The electronic structure and optical properties of zno wurtzite quantum wires with radius r. Piezoelectric,optical and electrical characterization of. The synthesized nanoparticles retained the wurtzite hexagonal structure, which was confirmed by xray diffraction studies. To unravel this enigma, we have re investigated the synthesis of undoped zincdeficient zinc oxide nanoparticles. Firstprinciples study on zno nanoclusters with hexagonal prism structures. Introduction zinc oxide zno is a iivi compound semiconductor having wide band gap of 3. Wurtzite nio wnio has been found to display halfmetallicity. Taking into account the so interaction, the energy bands of zno can be calculated by the epm. The semiconductor zno has gained substantial interest in the research community in part because of its large. Structures of wurtzite zno solid solutions with mgo and. In the recent era zinc oxide nanoparticles attracted the researchers due. The wurtzite crystal structure of zno with the lattice parameters a and c indicated in a, and the calculated band structure of zno using the hse hybrid functional in b. The physical and chemical properties of wurtzite zno wzno has been extensively. Thermal conductivity of wurtzite zincoxide from first.
Electronic structure of zno wurtzite quantum wires. Wurtzite zincoxide wzno is a wide bandgap semiconductor that holds promise in power electronics applications, where heat dissipation is. We investigated the properties of vibrational modes of the semiconductors such as zno, gan and 6hsic belonging to the wurtzite structure in order to characterize the materials. The investigations were conducted by xray absorption fine structure spectroscopy xafs technique for the samples prepared with different heating and doping processes. A convenient route at ambient conditions was employed to prepare narrowdispersed zno nanorods in terms of size and morphology. Multiwavelength raman scattering of nanostructured al. In recent years, zinc oxide zno has attracted a lot of. Structural and morphology of zno nanorods synthesized. The wurtzite structure has an abab hexagonal close packing hcp structure. Transmission electron microscopy and xray diffraction were used to characterize the structurally uniform and wellproportioned products. We observed that the freestanding gaas nws retain the pure 2h. The energy of the valenceband maximum vbm was set to zero. The wurtzite structure family has a few important members, such as zno, gan, aln, zns, and cdse, which are important materials for applications in optoelectronics, lasing, and piezoelectricity.
Synthesis of zno nanocrystals with hexagonal wurtzite. With an exciton binding energy of 60 mev and wide direct. Unravelling the origin of the giant zn deficiency in. Pdf the development of technologically important material zincblende zno has been hindered due to the. It can be considered as being formed by the penetration of two hcp lattices see fig. Combining microelectromechanical system mems technology with selfassembled. Surface, optical and photocatalytic properties of rb doped. Journal of nanomaterials hindawi publishing corporation. By continuing to use this site you agree to our use of cookies. The nanocrystals of zno with hexagonal wurtzite structure were characterized by xray powder diffraction xrd, transmission electron microscopy tem, scanning electron microscopy sem, uvvis absorption and ftir spectroscopy techniques. The change in the crystal and electronic structure properties of wurtzite zno nanoparticles was studied according to mn doping in the powder samples.
1302 772 462 955 1396 733 924 1102 1385 1332 442 1190 919 497 331 1432 1229 724 181 414 888 417 1478 862 591 844 557 532 910 450 94 1133 344 658 1192 37 627 489 1045 1286 1203