Interstitial oxygen in zinc oxide single crystals

Hausmann, A.; Schallenberger, B.

doi:10.1007/bf01352351

Cited by 43 publications

(31 citation statements)

References 28 publications

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“…It is also shown that the integrated area increases essentially with an increase in dry temperatures. Our g-values are in line with the value reported previously from the ZnO single crystal, ceramic and powder [3,17,18]. These results showed that the ESR signal at g 1.96 in our samples appears to its fullest intensity without irradiation or/and simultaneous illumination the samples.…”

Section: Resultssupporting

confidence: 92%

“…The intensity, on the other hand increased with increasing dry temperature. The ESR signal in the sample dried with Td = 100˚C was found very weak compared to samples dried Although the origin of the signal with these g-values are still unclear, it has been demonstrated in the literature that the paramagnetic signal around g value of 1.96 appears often owing to residual impurities in ZnO (F, Cl, Br and Al, Ga, In; with the g-value being practically independent of the type of impurities) as well as intrinsic defects like oxygen vacancies or Zn interstitial [3,[17][18][19][20][21][22][23]. Recently, Hoffmann et al [22] to the crystal c-axis), D1 and D2 centers.…”

Section: Resultsmentioning

confidence: 90%

“…In early publications [3,17,19], it was shown that the g value at 1.96 correlates with electron conductivity and originates from shallow donors. Kasai [3] and Hausmann et al [18] argued that this line are related to the oxygen vacancies, whereas the EPR signal with the g values of g// = 1.9945 and g┴ = 1.9960 was attributed by Hausmann and Schallenberger [18] to the oxygen atom in the tetrahedral interstitial position. Several authors [21,[24][25][26][27], however associated the EPR signal at g// = 1.9945 and g┴ = 1.9960 to an oxygen vacancy V0 + charge states, that are observed only in irradiated ZnO crystals under illumination and stable up to 400˚C -500˚C annealing.…”

Section: Resultsmentioning

confidence: 97%

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Synthesis and Spectroscopic Characterization of Undoped Nanocrytalline ZnO Particles Prepared by Co-Precipitation

Prakoso¹,

Saleh²

2012

MSA

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A series of undoped nanocrystalline ZnO particles were successfully synthesized at various dry temperatures (100˚C -600˚C) using coprecipitation method. The samples were characterized using a variety of experimental methods such as x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), thermal analysis TG-DTA, UV-vis spectroscopy, infrared absorption spectroscopy (FTIR) and electron spin resonance spectroscopy (ESR). According to XRD analysis, all of our ZnO samples posses the hexagonal wurzite structure with average crystallite size increased ranging from 19 -23 nm as dry temperature increased. Optical absorption spectra show that the band gap shifted to the lower energy with increasing crystallite size. ESR measurements showed the resonance of electron centers with the g values of about 1.96. With increasing dry temperature we observed the decrease of the g values and the increase of the intensities of the ESR signal. In addition an increase in dry temperature results in a pronounce decrease of OH local vibrational modes. The results from ESR measurements are well supported by the results obtained from Infrared absorption spectroscopy and thermal analysis measurements.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 97%

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Synthesis and Spectroscopic Characterization of Undoped Nanocrytalline ZnO Particles Prepared by Co-Precipitation

Prakoso¹,

Saleh²

2012

MSA

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“…In earlier paper [32][33][34], it was shown that the g-value 1.96 of ESR line in undoped ZnO correlates well with electron conductivity and originates from shallow donors. Later, Kasai [32] and Hausmann [35] argued that shallow donors in ZnO are related to the oxygen vacancy, whereas the low field signal with the g-value of 1.99 is generally attributed to singly ionized oxygen vacancies or unpaired electron trapped on an oxygen vacancy site. By analyzing and comparing our ESR signal with signal reported in the literature, we believed that the ESR spectra obtained for samples in the present study can both be ascribed to Ce 3+ and an unpaired electron trapped in Ce 4+ (a narrow line) or Ce 3+ , although it is impossible to distinguish unambiguously between the two cases from knowledge of the g-value alone, since the Ce 4+ ion is not paramagnetic center.…”

Section: Resultsmentioning

confidence: 99%

Characteristics and Photocatalytics Activities of Ce-Doped ZnO Nanoparticles

Djaja¹,

Saleh²

2013

MSA

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Ce-doped ZnO nanoparticles with various doping concentrations of cerium ion were prepared by the co-precipitation method. All prepared nanoparticles were characterized by electron spin resonance (ESR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectroscopy. All nanoparticles show X-ray diffraction pattern that matched with ZnO in its wurzite structure and average grain size was in the range of 13 -16 nm. UV-Vis measurements indicated a red shift of the photophysical response of ZnO after doping that was exhibited in reflection spectra in the visible region between 300 -800 nm. In addition, it has been found from electron spin resonance measurements that defects, which are likely to be oxygen vacancy and an electron trapped at cerium site are formed in our Ce-doped ZnO particles. Photocatalytic activities of Ce-doped ZnO were evaluated by irradiating the nanoparticles solution to ultraviolet light by taking methyl orange as organic dye. The experiment demonstrated that the photodegradation increased as doping concentrations increased at first and then decreased when the doping concentration exceeded 9 at%. It is proposed that the photocatalytic activity is strongly dependent on the formation of oxygen vacancy and an electron trapped at cerium site.

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“…Therefore, the defect chemistry of ZnO has been investigated in a large number of articles. However, the fundamental knowledge on the native defects is still lacking; the defect species that dominate the electrical properties of undoped ZnO still raises a lot of controversy [9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Grain growth kinetics for B2O3-doped ZnO ceramics

Yüksel

Özkan

2015

Materials Science-Poland

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Grain growth kinetics in 0.1 to 2 mol % B 2 O 3 -added ZnO ceramics was studied by using a simplified phenomenological grain growth kinetics equation G n = K 0 ·t·exp(−Q/RT) together with the physical properties of sintered samples. The samples, prepared by conventional ceramics processing techniques, were sintered at temperatures between 1050 to 1250°C for 1, 2, 3, 5 and 10 hours in air. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 0.1 mol % B 2 O 3 -doped ZnO ceramics were found to be 2.8 and 332 kJ/mol, respectively. By increasing B 2 O 3 content to 1 mol %, the grain growth exponent value (n) and the activation energy decreased to 2 and 238 kJ/mol, respectively. The XRD study revealed the presence of a second phase, Zn 3 B 2 O 6 formed when the B 2 O 3 content was 1 mol %. The formation of Zn 3 B 2 O 6 phase gave rise to an increase of the grain growth kinetic exponent and the grain growth activation energy. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 2 mol % B 2 O 3 -doped ZnO ceramics were found to be 3 and 307 kJ/mol, respectively. This can be attributed to the second particle drag (pinning) mechanism in the liquid phase sintering.

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Interstitial oxygen in zinc oxide single crystals

Cited by 43 publications

References 28 publications

Synthesis and Spectroscopic Characterization of Undoped Nanocrytalline ZnO Particles Prepared by Co-Precipitation

Synthesis and Spectroscopic Characterization of Undoped Nanocrytalline ZnO Particles Prepared by Co-Precipitation

Characteristics and Photocatalytics Activities of Ce-Doped ZnO Nanoparticles

Grain growth kinetics for B2O3-doped ZnO ceramics

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