Vacancy-Type Defects in Electron and Proton Irradiated II-VI Compounds

1998 ◽  
Vol 510 ◽  
Author(s):  
S. Brunner ◽  
W. Puff ◽  
P. Mascher ◽  
A.G. Balogh
Keyword(s):  
Band Gap ◽  
Proton Irradiation ◽  
Positron Lifetime ◽  
Wide Band ◽  
Compound Semiconductors ◽  
Doppler Broadening ◽  
Wide Band Gap ◽  
Radiation Induced ◽  
Induced Defects ◽  
Mev Protons

AbstractIn this contribution we present a study aimed at comparing results of positron-lifetime and Doppler-broadening measurements on the wide-band-gap compound semiconductors ZnS, ZnSe, and ZnTe. To investigate the basic properties of intrinsic and radiation induced defects the samples were irradiated either with 3 MeV protons or 1 MeV electrons. The isochronal annealing was performed in an Ar atmosphere. It was found that electron and proton irradiation cause different changes in the positron annihilation characteristics. Several annealing stages were observed, related to the annealing of variously sized vacancy complexes.

Microstructural Evolution of Radiation Induced Defects In ZnO During Isochronal Annealing

1998 ◽  
Vol 540 ◽  
Author(s):  
S. Brunner ◽  
W. Puff ◽  
P. Mascher ◽  
A.G. Balogh
Keyword(s):  
Room Temperature ◽  
Proton Irradiation ◽  
Positron Lifetime ◽  
Thermal Evolution ◽  
Isochronal Annealing ◽  
Doppler Broadening ◽  
Thermal Dependence ◽  
Radiation Induced ◽  
Induced Defects ◽  
Mev Protons

AbstractIn this study we discuss the microstructural changes after electron and proton irradiation and the thermal evolution of the radiation induced defects during isochronal annealing. The nominally undoped samples were irradiated either with 3 MeV protons to a fluence of 1.2× 1018 p/cm2 or with 1 MeV electrons to a fluence of 1×1018 e/cm2. The investigation was performed with positron lifetime and Doppler-broadening measurements. The measurements were done at room temperature and in some cases down to 10 K to investigate the thermal dependence of the trapping characteristics of the positrons.

Proton Irradiation Induced Defects in 611- and 4H-SiC

1998 ◽  
Vol 540 ◽  
Author(s):  
Werner Puff ◽  
Adam G. Balogh ◽  
Peter Mascher
Keyword(s):  
Proton Irradiation ◽  
Positron Lifetime ◽  
Doppler Broadening ◽  
Defect Complexes ◽  
Radiation Induced ◽  
Positron Lifetime Spectroscopy ◽  
Induced Defects ◽  
Irradiation Induced Defects ◽  
Type Sample

AbstractAnnealing of defects in proton irradiated bulk n-type 6H- and semi-insulating 4H-SiC has been investigated by positron lifetime spectroscopy and Doppler-broadening measurements. For the n-type sample radiation induced defects in dependence of the proton fluence were studied. Three or four annealing stages were found, during which the formation of larger defect complexes could be observed.

Radiation-Induced Defects in Electron and Proton Irradiated ZnS

1998 ◽  
Vol 540 ◽  
Author(s):  
S. Brunner ◽  
W. Puff ◽  
P. Mascher ◽  
A.G. Balogh
Keyword(s):  
Vapour Deposition ◽  
Proton Irradiation ◽  
Positron Lifetime ◽  
Chemical Vapour ◽  
Isochronal Annealing ◽  
Doppler Broadening ◽  
Defect Complexes ◽  
Radiation Induced ◽  
The Stability ◽  
Induced Defects

AbstractIn this contribution, we present a study aimed at investigating the microstructural changes of ZnS single crystals and CVD (chemical vapour deposition) grown crystals after electron and proton irradiation. Positron lifetime and Doppler-broadening measurements were performed to investigate the stability of the radiation induced defects and possible clustering mechanisms during isochronal annealing. After electron as well as proton irradiation the significant changes in the annihilation characteristics are indications of radiation induced open-volume-type defects. It is found that electron and proton irradiation causes different changes in the positron annihilation characteristics. After electron irradiation a significant defect component is observed which can be attributed to the annihilation in monovacancies. During isochronal annealing agglomerations to divacancy-type defects take place. Proton irradiation reveals a significantly different defect structure. Isochronal annealing causes agglomerations to larger defect complexes. The observed annealing stages are indications of the annealing of variously sized vacancy complexes.

Studies of Defects in ZnO by Positron Annihilation

1995 ◽  
Vol 378 ◽  
Author(s):  
Werner Puff ◽  
Sebastian Brunner ◽  
Peter Mascher ◽  
Adam G. Balogh
Keyword(s):  
Positron Annihilation ◽  
Colour Change ◽  
Doppler Broadening ◽  
Positron Annihilation Lifetime ◽  
Dark Orange ◽  
Radiation Induced ◽  
Induced Defects ◽  
Annealing Experiments ◽  
Mev Protons ◽  
Yellowish White

AbstractIn order to investigate the basic properties of radiation-induced defects in ZnO crystals, positron annihilation lifetime and Doppler-broadening measurements were performed on crystals sinterd for 18 hours at 1200 °C and irradiated with 3 MeV protons at 223 K. The irradiation induced a colour change of the specimens from the original yellowish-white to dark orange or even brown. Isochronal annealing experiments showed three annealing stages, centred at about 150 °C, 500 – 550 °C, and 750 °C, respectively. These stages are related to the annealing of variously sized vacancy complexes.

Vacancy-Type Defects in as-Grown and Proton-Irradiated 6H-SiC

1998 ◽  
Vol 512 ◽  
Author(s):  
Werner Puff ◽  
Peter Mascher ◽  
Adam G. Balogh
Keyword(s):  
Positron Lifetime ◽  
Doppler Broadening ◽  
Defect Complexes ◽  
Radiation Induced ◽  
Positron Lifetime Spectroscopy ◽  
P Type ◽  
Induced Defects

ABSTRACTAnnealing of defects in as-grown and proton irradiated bulk n- and p-type 6H-SiC has been investigated by positron lifetime spectroscopy and Doppler-broadening measurements. The grown-in defects do not anneal out until 1600 °C, whereas the radiation induced defects show three main annealing stages well below this temperature. During annealing, the formation of larger defect complexes can be observed.

An Investigation of Point Defects in NiAl Using Positron Annihilation Techniques

1998 ◽  
Vol 552 ◽  
Author(s):  
Werner Puff ◽  
Bernd Logar ◽  
Adam G. Balogh
Keyword(s):  
Positron Annihilation ◽  
Point Defects ◽  
Proton Irradiation ◽  
Positron Lifetime ◽  
Composition Range ◽  
Isochronal Annealing ◽  
Doppler Broadening ◽  
Positron Lifetime Spectroscopy ◽  
Induced Defects

ABSTRACTVacancy-like defects in NiAl in the composition range 47 at.-% < CNi < 53 at.-% are investigated by means of positron lifetime spectroscopy and Doppler-broadening measurements. The observed lifetimes in the annealed samples confirm that defects are quenched-in during the production of the samples. Isochronal annealing of samples quenched at 1600°C and after proton irradiation show that the induced defects are quite different.

Detection of Interstitial Molecules in Wide Band Gap Materials Using Cathodoluminescence Microanalysis

1999 ◽  
Vol 5 (S2) ◽  
pp. 732-733
Author(s):  
M.A. Stevens Kalceff
Keyword(s):  
Electron Beam ◽  
Band Gap ◽  
Indirect Evidence ◽  
Analytical Techniques ◽  
Wide Band ◽  
In Situ Monitoring ◽  
Wide Band Gap ◽  
Special Cases ◽  
Induced Defects ◽  
Irradiation Induced Defects

Cathodoluminescence (CL) microanalysis (spectroscopy and microscopy) enables both pre-existing and irradiation induced defects in the bulk and surface defect structure of wide band gap materials (i.e. semiconductors and insulators) to be monitored and characterized with high spatial resolution and sensitivity. The local micro-volume of specimen may be selected for investigation by varying the electron beam parameters. CL micro analytical techniques allow the in situ monitoring of electron irradiation induced defects and the investigation of irradiation induced electromigration of mobile charged defect species. Irradiation can result in the formation of defects and /or the transformation of existing defect precursors. CL emissions from a material are usually associated with native and impurity defects of the host lattice, however in special cases CL microanalysis can provide direct or indirect evidence for the presence of interstitial molecular species in a material. Atomic displacements from the normal bonding (i.e. defect free) sites induced by an electron beam can result from either knock-on, or radiolytic processes, depending on the incident electron beam energy.

Vacancy-Type Defects in Electron and Proton Irradiated II- VI Compounds

1996 ◽  
Vol 439 ◽  
Author(s):  
S. Brunner ◽  
W. Puff ◽  
P. Mascher ◽  
A. G. Balogh ◽  
H. Baumann
Keyword(s):  
Positron Annihilation ◽  
Proton Irradiation ◽  
Basic Properties ◽  
Radiation Induced ◽  
Induced Defects ◽  
Mev Protons

AbstractIn this contribution, we present a study aimed at investigating the basic properties of radiation induced defects in ZnS and ZnO and the influence of the atmosphere on the annealing characteristics of the defects. Positron annihilation experiments (both lifetime and Dopplerbroadening measurements) were performed on both single- and polycrystalline samples, irradiated with 3 MeV protons or 1 MeV electrons. For ZnS it was found that both electron and proton irradiation caused significant changes in the positron annihilation characteristics. The annealing of proton irradiated ZnS in air leads to significant oxidation and eventual transformation into ZnO.

Interactions of wide band gap single crystals with 248 nm excimer laser radiation. III. The role of cleavage‐induced defects in MgO

1993 ◽  
Vol 74 (6) ◽  
pp. 3758-3767 ◽  
Author(s):  
J. T. Dickinson ◽  
L. C. Jensen ◽  
R. L. Webb ◽  
M. L. Dawes ◽  
S. C. Langford
Keyword(s):  
Laser Radiation ◽  
Band Gap ◽  
Single Crystals ◽  
Excimer Laser ◽  
Wide Band ◽  
Wide Band Gap ◽  
Excimer Laser Radiation ◽  
Induced Defects
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