Magnetic resonance studies of ZnO

Carlos, W. E.; Glaser, E. R.; Look, David C.

doi:10.1016/s0921-4526(01)00850-x

Cited by 122 publications

(94 citation statements)

References 13 publications

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“…These treatments cause the following effects: ͑1͒ an optical absorption band appears in the near-edge region, extending out to 550 nm; ͑2͒ the concentration of neutral shallow donors is greatly decreased; and ͑3͒ the electron paramagnetic resonance ͑EPR͒ signal of the neutral nitrogen acceptor can be photoinduced. This nitrogen EPR signal has been recently reported by Carlos, Glaser, and Look 14 and is unambiguously assigned to the neutral nitrogen acceptor because of its uniquely characteristic three-line hyperfine pattern, arising from a nearly 100% abundant Iϭ1 nucleus ͑in this case, the 14 N isotope͒. We have found that this neutral nitrogen EPR signal can be photoinduced at low temperature with a variety of laser wavelengths ͑e.g., 364, 442, 458, and 514 nm͒.…”

supporting

confidence: 71%

Production of nitrogen acceptors in ZnO by thermal annealing

Garces

Giles

Halliburton

et al. 2002

Applied Physics Letters

200

107

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Nitrogen acceptors are formed when undoped single crystals of zinc oxide (ZnO) grown by the chemical-vapor transport method are annealed in air or nitrogen atmosphere at temperatures between 600 and 900 °C. After an anneal, an induced near-edge absorption band causes the crystals to appear yellow. Also, the concentration of neutral shallow donors, as monitored by electron paramagnetic resonance (EPR), is significantly reduced. A photoinduced EPR signal due to neutral nitrogen acceptors is observed when the annealed crystals are exposed to laser light (e.g., 364, 442, 458, or 514 nm) at low temperature. The nitrogens are initially in the nonparamagnetic singly ionized state (N−) in an annealed crystal, because of the large number of shallow donors, and the light converts a portion of them to the paramagnetic neutral acceptor state (N0).

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supporting

confidence: 71%

Production of nitrogen acceptors in ZnO by thermal annealing

Garces

Giles

Halliburton

et al. 2002

Applied Physics Letters

200

107

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“…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%

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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“…18,59 Nitrogen forms a substitutional defect in ZnO, 28 where it leads to introduction of a hole. Symmetry constraints allow the hole to be mainly associated with a nearly degenerate pair of N 2p orbitals lying in the ab plane of the wurtzite structure or in a nondegenerate 2p orbital parallel to the c axis.…”

Section: F Substituted Nitrogen N Omentioning

confidence: 99%

“…7 and 24-26͒ were originally studied in the 1960s and 1970s by magnetic resonance and optical techniques. Recent magnetic resonance, [27][28][29][30][31][32] carrier mobility, 33 positron annihilation spectroscopy, 34 and first-principles calculations [35][36][37] have given a fuller picture of defect-induced electronic states in ZnO. Magnetic resonance techniques 8,9,38 have been applied to Zn 1−x Co x O and Zn 1−x Mn x O films and nanoclusters.…”

Section: Introductionmentioning

confidence: 99%