Defect studies in annealed ZnO by positron annihilation spectroscopy

Sanyal, Dirtha; Roy, Tufan; Chakrabarti, Mahuya; Dechoudhury, Siddhartha; Bhowmick, Debasis; Chakrabarti, Alok

doi:10.1088/0953-8984/20/04/045217

Cited by 29 publications

(24 citation statements)

References 31 publications

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“…An experimental study corresponding to those findings has been performed by Sanyal et al [57]. The group was ball-milling ZnO powder and subsequently annealing it in air up to 873 K. Applying positron annihilation spectroscopy (PAS), they found mainly Zn vacancies inside the as-milled powders.…”

Section: Role Of the Defects 41 Intrinsic Defects In Znomentioning

confidence: 86%

“…The parameters investigated are the isomer shift, the quadrupole and the magnetic hyperfine splitting at the nucleus. Early investigations on solid solutions of 57 Fe, Zn and O mainly revealed oxide spinel secondary phases to be responsible for magnetic sextets observed [42,43]. There are other methods basing on radioactive probes which definitely have the potential to give more insight into the origin of ferromagnetic properties in TM doped ZnO.…”

Section: Analysis Techniques Inmentioning

confidence: 99%

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Non‐DMS related ferromagnetism in transition metal doped zinc oxide

Potzger

Zhou

2009

Physica Status Solidi (b)

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We review pitfalls in recent efforts to make a conventional semiconductor, namely ZnO, ferromagnetic by means of doping with transition metal ions. Since the solubility of those elements is rather low, formation of secondary phases and the creation of defects upon low temperature processing can lead to unwanted magnetic effects. Among others, ion implantation is a method of doping, which is highly suited for the investigation of those effects. By focussing mainly on Fe, Co or Ni implanted ZnO single crystals we show that there are manifold sources for ferromagnetism in this material which can easily be confused with the formation of a ferromagnetic diluted magnetic semiconductor (DMS). We will focus on metallic as well as oxide precipitates and the difficulties of their identification.Comment: 24 pages, 22 figure

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Section: Role Of the Defects 41 Intrinsic Defects In Znomentioning

confidence: 86%

Section: Analysis Techniques Inmentioning

confidence: 99%

Non‐DMS related ferromagnetism in transition metal doped zinc oxide

Potzger

Zhou

2009

Physica Status Solidi (b)

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“…The presence of oxygen vacancies expands the ZnO lattice [18]. It has been reported [19,20] that a significant amount of oxygen vacancy has been created and interstitial zinc atoms have been obtained enough energy and reverted to the crystal lattice site (recombined with Zn vacancies) by annealing the polycrystalline ZnO in air at about 500 °C. Furthermore, it has been reported that the interstitial zinc atoms have been reverted to the crystal lattice site in the ZnO:Co films when annealed in air at 600 °C [21].…”

Section: Methodsmentioning

confidence: 99%

Structure and magnetism of manganese‐doped ZnO powder samples

Ahmed¹

2009

Cryst. Res. Technol.

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The magnetic and structural properties of manganese-doped ZnO powder samples prepared by a solid state method are reported. Magnetization measurements indicate ferromagnetic behavior, with hysteresis observed in the M vs. H behavior at 300 K. Coercive fields were <100 Oe at 300 K. Temperature-dependent magnetization measurements showed evidence for ordering temperatures of >300 K. However, the results show that ferromagnetism originates from the doped matrix rather than any type of magnetic cluster and the ferromagnetism is due to the defects and/or oxygen vacancies confined to the surface of the grains.

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“…Annealing of crystals is one possible way of recovering defects or removing them. The study of defects in ZnO through annealing has been performed using the Hall effect, 9-11 positron annihilation spectroscopy, 12 x ray diffraction, Rutherford backscattering spectroscopy (RBS), admittance spectroscopy, 13 cathodoluminescence, and photoluminescence. 14 In this paper, we study the effects of annealing on ZnO and the electrical properties of the devices formed on the annealed material.…”

Section: Introductionmentioning

confidence: 99%

Effects of high temperature annealing on single crystal ZnO and ZnO devices

Mtangi

Auret

Diale

et al. 2012

Journal of Applied Physics

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AlN thin film transducers for high temperature non-destructive testing applications J. Appl. Phys. 111, 074510 (2012) Fast programming metal-gate Si quantum dot nonvolatile memory using green nanosecond laser spike annealing Appl. Phys. Lett. 100, 143501 (2012) Al2O3/InAs metal-oxide-semiconductor capacitors on (100) and (111)B substrates Appl. Phys. Lett. 100, 132905 (2012) Sub-diffraction-limit semiconductor resonators operating on the fundamental magnetic resonance Appl. Phys. Lett. 100, 131113 (2012) Additional information on J. Appl. Phys. We have systematically investigated the effects of high-temperature annealing on ZnO and ZnO devices using current voltage, deep level transient spectroscopy (DLTS) and Laplace DLTS measurements. Current-voltage measurements reveal the decrease in the quality of devices fabricated on the annealed samples, with the high-temperature annealed samples yielding devices with low barrier heights and high reverse currents. DLTS results indicate the presence of three prominent defects in the as-received samples. Annealing the ZnO samples at 300 C, 500 C, and 600 C in Ar results in an increase in reverse leakage current of the Schottky contacts and an introduction of a new broad peak. After 700 C annealing, the broad peak is no longer present, but a new defect with an activation enthalpy of 0.18 eV is observed. Further annealing of the samples in oxygen after Ar annealing causes an increase in intensity of the broad peak. High-resolution Laplace DLTS has been successfully employed to resolve the closely spaced energy levels. V C 2012 American Institute of Physics. [http://dx

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Defect studies in annealed ZnO by positron annihilation spectroscopy

Cited by 29 publications

References 31 publications

Non‐DMS related ferromagnetism in transition metal doped zinc oxide

Non‐DMS related ferromagnetism in transition metal doped zinc oxide

Structure and magnetism of manganese‐doped ZnO powder samples

Effects of high temperature annealing on single crystal ZnO and ZnO devices

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