ESR investigation of the oxygen vacancy in pure and Bi2O3-doped zno ceramics

Pöppl, Álan Gomes; Völkel, G.

doi:10.1002/pssa.2211150127

Cited by 39 publications

(21 citation statements)

References 12 publications

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“…At T < 50K the signal exhibits an asymmetrical lineshape typical for a centre with axial symmetry. The V : signal becomes symmetrical for T z 100 K due to an increase of the line width ABpp analogous to the ESR signal of VJ centres in undoped ZnO ceramics [4]. For T = 27 K the main values of the g-tensor g, = 1.9557 f 0.0008 and gll = 1.9573 f 0.0008 estimated by a computer simulation of the powder pattern are in accordance with the single crystal g values [5].…”

Section: Zno Raw Materialssupporting

confidence: 64%

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ESR and photo-ESR investigations of the V0+ centre in ZnO raw material and Li-doped ZnO ceramic powder

Pöppl

Völkel

1990

phys. stat. sol. (a)

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ESR and photo‐ESR measurements of the V 0+ centre are performed to determine the charge states of the oxygen vacancies in ZnO raw material and Li‐doped ZnO ceramics. The temperature dependence of the relative ESR intensity and the optical excitation of the ESR signal of the V 0+ centre are investigated. The results show, that in both samples the oxygen vacancies exist in the V 02+ and V 0+ state only. The ionization energy of the V 0+ centre is determined by analysing the decay of the intensity of the V 0+ signal after turning off the optical excitation.

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Section: Zno Raw Materialssupporting

confidence: 64%

“…The investigation of the temperature dependence of the intensity of the ESR signal of the V,' centre presented in a former paper [4] showed that the oxygen vacancies in undoped ZnO ceramics exist in the V: and V, X states. The intensity of the V i signal could not be influenced by optical excitation of the sample.…”

Section: Introductionmentioning

confidence: 98%

ESR and photo-ESR investigations of the V0+ centre in ZnO raw material and Li-doped ZnO ceramic powder

Pöppl

Völkel

1990

phys. stat. sol. (a)

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“…In 2002 stimulated by a theoretical work of Van de Walle [51] hydrogen could be identified as a shallow donor too [52]. The "1.96" resonance has been attributed for a long time with the singly ionized charge state of the oxygen vacancy (F + -center) [53][54][55], although the F + -center could only be detected after electron or neutron irradiation of ZnO [56][57][58]. As to acceptor related centers (apart from transition metal elements which will not be considered here) three of them were detected again after particle irradiation of undoped ZnO [59][60][61][62][63].…”

Section: Magnetic Resonance Investigationsmentioning

confidence: 99%

Bound exciton and donor–acceptor pair recombinations in ZnO

Meyer

Alves

Hofmann

et al. 2004

Physica Status Solidi (b)

1,581

153

1,161

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The optical properties of excitonic recombinations in bulk, n-type ZnO are investigated by photoluminescence (PL) and spatially resolved cathodoluminescence (CL) measurements. At liquid helium temperature in undoped crystals the neutral donor bound excitons dominate in the PL spectrum. Two electron satellite transitions (TES) of the donor bound excitons allow to determine the donor binding energies ranging from 46 to 73 meV. These results are in line with the temperature dependent Hall effect measurements. In the as-grown crystals a shallow donor with an activation energy of 30 meV controls the conductivity. Annealing annihilates this shallow donor which has a bound exciton recombination at 3.3628 eV. Correlated by magnetic resonance experiments we attribute this particular donor to hydrogen. The Al, Ga and In donor bound exciton recombinations are identified based on doping and diffusion experiments and using secondary ion mass spectroscopy. We give a special focus on the recombination around 3.333 eV, i.e. about 50 meV below the free exciton transition. From temperature dependent measurements one obtains a small thermal activation energy for the quenching of the luminescence of 10 ± 2 meV despite the large localization energy of 50 meV. Spatially resolved CL measurements show that the 3.333 eV lines are particularly strong at crystal irregularities and occur only at certain spots hence are not homogeneously distributed within the crystal contrary to the bound exciton recombinations. We attribute them to excitons bound to structural defects (Y-line defect) very common in II-VI semiconductors. For the bound exciton lines which seem to be correlated with Li and Na doping we offer a different interpretation. Li and Na do not introduce any shallow acceptor level in ZnO which otherwise should show up in donor -acceptor pair recombinations. Nitrogen creates a shallow acceptor level in ZnO. Donor -acceptor pair recombination with the 165 meV deep N-acceptor is found in nitrogen doped and implanted ZnO samples, respectively. In the best undoped samples excited rotational states of the donor bound excitons can be seen in low temperature PL measurements. At higher temperatures we also see the appearance of the excitons bound to the B-valence band, which are approximately 4.7 meV higher in energy.

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“…The presence of oxygen vacancies in ZnO has been known for some time, [13] and a number of methods are suitable for the preparation of surface-rich and nanoscaled ZnO.…”

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confidence: 99%