The structure, purity, crystallite size and the phase of the synthesized znomgo nanocomposites are confirmed by the powder xrd patterns. All evident peaks could be indexed as the zno wurtzite structure jcpds data card no. The chemical prototype is conventionally given as zns, although mineral wurtzite is a multicomponent alloy compound. Raman and photoluminescence properties of zno nanorods.
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. Plasmonmediated highly enhanced photocatalytic degradation of. Electronic structure of zno wurtzite quantum wires. It is found that the electron states are either twofold or fourfold degenerate. It occurs naturally as the mineral zincite, but most zinc oxide is. The electronic structure and optical properties of zno wurtzite quantum wires with radius r. Download amc data view text file download cif data view text file download diffraction data view text file view jmol 3d structure. Xray peak broadening analysis of zno nanoparticles derived.
Wurtzite zincoxide w zno is a wide bandgap semiconductor that holds promise in power electronics applications, where heat dissipation is of critical importance. Synthesis of zno nanocrystals with hexagonal wurtzite structure. Zinc blendewurtzite polytypism in nanocrystalline zno films. Synthesis and local structure of doped nanocrystalline. Our motivation is provided by recent experiments reporting ferromagnetism in mndoped wurtzite structure zno. Different solvents such as ethanol, ethanolwater and water mediated zinc oxidemagnesium oxide znomgo nanocomposites have been successfully synthesized by the facile precipitation process.
The energy of the valenceband maximum vbm was set to zero. Apr 09, 2018 this feature is not available right now. Usually found as black to dark reddishbrown massive resinous to submetallic material, also as botryoidal banded crusts, and more rarely as hemimorphic pyramidal, or tabular, crystals. Structural and optical properties of znomgo nanocomposites. Electronic structure of zno wurtzite quantum wires springerlink. Wurtzitetotetragonal structure phase transformation and. Since the volume per atom is the same, a given volume of reciprocal space for wurtzite contains approximately twice as many reciprocal lattice points. Transmission electron microscopy and xray diffraction were used to characterize the structurally uniform and wellproportioned products. Regularly shaped, singlecrystalline zno nanorods with. The lattice constants for several wurtzite structure semiconductors are given in table 9. The crystal structure of the zno nanocrystals as synthesized by both routes belongs to hexagonal wurtzite structure, which is very close with standard jcpds files. The hole effectivemass parameters of zno wurtzite material are calculated by the empirical pseudopotential method.
Wurtzite nio wnio has been found to display halfmetallicity. The reason for this is that the reduction of the lattice dimensions causes the interionic coulomb interaction to favor the ionicity more over the covalent nature. Using x ray broadening, crystallite sizes and lattice strain on the peak broadening of znonps were studied by using williamsonhall wh analysis and sizestrain plot. Basal dislocations having a burgers vector of in zinc oxide zno with the wurtzite structure are known to strongly affect physical properties in bulk. Surface xray diffraction and ab initio calculations. The lattice constants for several wurtzite structure semiconductors are given in. Xray analysis by williamsonhall and sizestrain plot. The asprepared specimen exhibits strong ultraviolet exciton emission at 385 nm and disappearance of visible defect emission. This semiconductor has high chemical, mechanical, and thermal stabilities at room temperature, a low electrical constant, a high electrochemical coupling index, a wide range of. It is well known that zno has three stable structures.
Wz can be considered as a stacking of alternating closepacked zn and o layers along the 0 0 0 1 direction with a stacking sequence corresponding to aabbaabbaabb, where the upper. Zinc oxide is an inorganic compound used in a number of manufacturing processes. Pdf wurtzite structure in ultrathin zno films on fe110. The transmission electron microscopy measurements show that the obtained zno nanorods have wellproportioned distribution with diameters about 30 nm, and the maximal lengths up to more than 2. Nacl structure at relatively modest external hydrostatic pressures. In particular, it is a direct wide bandgap semiconductor e g. 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. Zinc oxide zno is a binary iivi semiconductor compound with a hexagonal wurtzite structure and ntype electrical conductivity, with a direct energy wide band of 3. Raman and photoluminescence properties of zno nanorods with. However, the core structure of the basal dislocation remains unclear. We find that wurtzite mno a is not strongly energetically disfavored as compared with the ground state rocksalt mno, b shows strong magnetostructural coupling and c has a piezoelectric response that is larger than that of zno. Wurtzite lattice parameters such as the values of d, the distance between adjacent planes in the miller. The wurtzite structure has a hexagonal unit cell with two lattice parameters a and c. Different solvents such as ethanol, ethanolwater and water mediated zinc oxidemagnesium oxide zno mgo nanocomposites have been successfully synthesized by the facile precipitation process.
Interfaces between hexagonal and cubic oxides and their structure. The structure is composed of two interpenetrating hexagonal closed packed hcp sublattices, each of which include of one type of atom displaced with respect to each other along. Cdo occur in the cubic rocksalt structure under ordinarily conditions, zn1xmgxo and zn1xcdxo alloys are known to form the wurtzite structure when x is small. Unprecedented hexagonal wurtzite mno has been prepared by thermal decomposition of mnacac2 on a carbon template.
For the hexagonal structure of zno nanorods with 100 orientation. A first principles study of wurtzitestructure mno core. For example, nonpolar mplane zno instead of cplane coupling with znmgo or other. Xray diffraction xrd pattern reveals wurtzite structure of zno nanoparticles. Wurtzite zinc oxide zno is a remarkable multifunctional material with a distinctive property set and a huge range of existing and emerging applications look 2006. Zno nanoparticles were synthesized by microemulsion route in ws ratio of 5 at room temperature. The average mulliken charges are reported to be ranging from 0. The wurtzite crystal structure, named after the mineral wurtzite, is a crystal structure for various binary compounds. Repeat for each page excluding advertisement pages of the magazine.
Hexagonal wurtzite structure of zno is the most stable structure under ambient conditions, which belongs to the space group p6 3mc. Click browse, go to directory where you saved the printed pdfs. Structural characterization has been carried out by tem, saed, and a rietveld analysis using xrd. It is generally accepted that the addition of cdo in zno decreases the band gap whereas that of mgo increases the band gap. Wurtzite structure in ultrathin zno films on fe110. The crystal structures shared by zno are wurtzite b4, zinc blende. Thermal conductivity of wurtzite zincoxide from first. Each zinc atom is surrounded by four oxygen atoms, which are located. It has a hexagonal close packed array of s and the znii sit in tetrahedral 12 occupied sites in the lattice, giving a unit cell with 8 zn and 16 ss. Our data is in well agreement with the joint committee on powder diffraction standards jcpds card no jcpds pdf no 361451 1. This structure is a member of the hexagonal crystal system and consists of tetrahedrally coordinated zinc and sulfur atoms that are. Pdf structural and electronic properties of hydrogen doped. Prof using initial values for the wurtzite zno structure. Zno films are commonly known to crystallize only in a hexagonal wurtzite wz structure, which is the most stable zno structure under ambient conditions.
Strain, stress and energy density parameters were calculated for the xrd peaks of all the. 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. U parameters for the wurtzite structure of zns and zno. 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. Wurtzite structure of zno nanoparticles is belonging to. The crystalline structure of zno thin film samples was. 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 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. Zinc oxide is an inorganic compound with the formula zn o. One promising replacement material is doped zinc oxide. In a real zno crystal, the wurtzite structure deviates from the ideal arrangement.
Pdf phase formation of hexagonal wurtzite zno through. For viewing with the commercial version of crystalmaker, show details and options. Structural and optical characterization of zno nanoparticles. Wz can be considered as a stacking of alternating closepacked zn and o layers along the 0 0 0 1 direction with a stacking sequence corresponding to. Pdf structural and electronic properties of hydrogen. The wurtzite structure with p6 3mc symmetry is known as the groundstate structure of zno, while the nonpolar p6 3mmc structure is less stable than the polar p6 3mc structure and can be stabilized by an imposed strain.
The two important characteristics of the wurtzite structure are the noncentral symmetry and polar surfaces. Zinc blendewurtzite polytypism in nanocrystalline zno. Most transition metal oxides have a cubic rocksalt crystal structure, but zno and coo are the only stable transition metal oxides known to possess a hexagonal structure. Wurtzite zincoxide wzno is a wide bandgap semiconductor that holds promise in power electronics applications, where heat dissipation is of critical importance. Ab initio calculations on structural, electronic and optical. Its crystal structure is called the wurtzite crystal structure, to which it lends its name. However, large discrepancies exist in the literature on the thermal conductivity of wzno. Synthesis and characterization of nanocrystalline zno. For wurtzite, there are four atoms per unit cell in contrast to two for zincblende.
The nanocrystals of zno with hexagonal wurtzite structure were characterized by xray powder diffraction xrd, transmission electron microscopy tem. A convenient route at ambient conditions was employed to prepare narrowdispersed zno nanorods in terms of size and morphology. Download diffraction data view text file view jmol 3d structure. Dresselhaus effect in bulk wurtzite materials article pdf available in applied physics letters 918. Structures of wurtzite zno solid solutions with mgo and cdo. Cadmoselite cdse, greenockite cds, matraite zns and rambergite mns, in addition to wurtzite. Wurtzitetotetragonal structure phase transformation and size effect in zno nanorods j. In the extreme case u 12 this structure becomes the b k bn structure.
It can be found in rubbers, plastics, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, and firstaid tapes. Among the binary oxide semiconductors, zno is the only material with a wurtzite type structure that has a direct allowed band gap, except for the carcinogenic beo. Structure of the basal edge dislocation in zno mdpi. Complexes that adapt this structure include beo, zno, and a form of mns and the high temperature form of cucl. Because the band gap of zno is in the nearuv region, zno based optoelectronic devices can only operate at nearuv wavelengths, such as in uv leds 4 and uv lasers 5. We found that cell parameters and volume of the supercells decrease in h. This is consistent with the distribution of charge density difference in the plane along the caxis for zno wurtzite structure, where blue, red, and yellow colors indicate electron depletion, electron accumulation, and regions with minimal difference, respectively.
Xray peak broadening analysis of zno nanoparticles. So far, six structures of zno have been reported, including wurtzite wz p63mc space group,1 zincblend zb,2 rocksalt rs,3 a layered structure ly,4 a hexagonal structure hx ref. Print the page and save in some sequential order, for example 001. Comparative study on zinc oxide nanocrystals synthesized. Ab initio calculations on structural, electronic and. Draw wurtzite crystal structure with vesta zno example. An existential study on structural, optical and electronic. Mar 31, 2006 the electronic structure and optical properties of zno wurtzite quantum wires with radius r.
Raman, resonant raman and photoluminescence pl properties of zno nanorods that produced by simple solution chemical process are reported in this paper. Rod shape of zno nanoparticles of average particle size 10. The lattice constants of zno solid structure, its ratio ca 1. The p6 3mmc structure is commonly called a graphiticlike structure. The structure, purity, crystallite size and the phase of the synthesized zno mgo nanocomposites are confirmed by the powder xrd patterns.
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