Defect induced ferromagnetism in MgO and its exceptional enhancement upon thermal annealing: a case of transformation of various defect states

2017 ◽  
Vol 19 (19) ◽  
pp. 11975-11989 ◽  
Author(s):  
Nimai Pathak ◽  
Santosh Kumar Gupta ◽  
C. L. Prajapat ◽  
S. K. Sharma ◽  
P. S. Ghosh ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Defect States ◽  
Micron Size ◽  
Cluster Vacancy

Micron size MgO particles showed various defect induced ferromagnetism with an exceptional enhancement upon thermal annealing due to transformation of one kind of cluster vacancy to another.

The influence of thermal annealing on the electronic defect states in nanocrystalline CVD diamond films

2008 ◽  
Vol 205 (9) ◽  
pp. 2158-2162 ◽  
Author(s):  
Z. Remes ◽  
A. Kromka ◽  
J. Potmesil ◽  
M. Vanecek
Keyword(s):  
Thermal Annealing ◽  
Diamond Films ◽  
Cvd Diamond ◽  
Defect States ◽  
Electronic Defect

Defect States Induced by Rapid Thermal Annealing in Virgin or Implanted Czochralski-Grown Silicon

1986 ◽  
Vol 74 ◽  
Author(s):  
M. Remram ◽  
D. Barbier ◽  
J.-F. Joly ◽  
A. Laugier
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Schottky Contacts ◽  
High Dose ◽  
Hole Trap ◽  
Defect States ◽  
Incoherent Light ◽  
Boron Doped ◽  
Doped Silicon ◽  
State Generation

AbstractDefect state generation in either virgin or implanted CZ silicon has been investigated by means of capacitance transient spectroscopy (DLTS) after rapid thermal annealing (RTA), using an incoherent light furnace and variable cycle parameters. No electron traps were dectected with gold Schottky contacts made on virgin phosporous-doped silicon annealed for 5 sec at any temperature. On the otherhand 3 hole trap levels H1(0.45 eV), H2(0.29 eV) and H3(0.31 eV) have been observed in boron-doped silicon (Al Schottky contacts) after a 5 sec temperature plateau between 850 and 1050°C. Peak concentrations ranging from 1013 to 1014 cm−3 were measured after annealing at 1000°C for the three hole traps. By increasing the plateau duration up to 20 sec hole traps were no longer detected in boron-doped silicon. Furthermore in As+ or PF5+-implanted and rapidly annealed N+/P junctions the H3(0.31 eV) level was replaced by another hole trap H4(0.4 eV), which appeared within specific conditions (RTA parameters, implant dose and species). Moreover an electron trap E(0.55 eV) was only detected in the high dose As+-implanted junctions after annealing for 10 sec at 1100°C. The probable metallic origin of the observed defect states and the RTA parameter dependence of the hole trap concentrations suggest gettering and trapping in interstitial sites as possible mechanisms involved in RTA.

Toward a Practical Model of a-Si:H Defects in Intensity-Time-Temperature Space

1994 ◽  
Vol 336 ◽  
Author(s):  
D. Caputo ◽  
J. Bullock ◽  
H. Gleskova ◽  
S. Wagner
Keyword(s):  
Light Intensity ◽  
Fermi Level ◽  
Amorphous Silicon ◽  
Thermal Annealing ◽  
Hydrogenated Amorphous Silicon ◽  
Defect States ◽  
Quasi Fermi Level ◽  
Practical Model ◽  
Density Of Defect States ◽  
Hydrogenated Amorphous

ABSTRACTIn this paper we develop a model of the defect kinetics in hydrogenated Amorphous silicon (a:Si:H) with the goal of predicting the density of defect states g (E) established by any given light intensity I, for arbitrary times t and temperatures T. While we build on widely accepted expressions for the the rates of light-induced and thermal annealing, we examine in more detail the light induced annealing (LIA) term. The model shows that the LIA process can be described with the thermal annealing term if a suitable reduction to the annealing energy is introduced. This reduction depends on the light intensity such as to suggest a relation to the shift of the electron quasi-Fermi level under illumination.

Defect States in GaAs after Rapid Thermal Annealing

1985 ◽  
Vol 46 ◽  
Author(s):  
R. A. Street ◽  
N. M. Johnson ◽  
R. D. Burnham
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Deep Levels ◽  
Luminescence Spectra ◽  
Defect States ◽  
Type Conversion ◽  
Annealing Temperatures ◽  
Luminescence Peak ◽  
Capacitance Voltage ◽  
Anneal Temperature

AbstractElectronic deep levels in GaAs have been investigated by correlated luminescence and DLTS measurements on material in which the defects were systematically perturbed by rapid thermal annealing. The samples were grown by MOCVD and encapsulated with silicon nitride. Annealing was performed at temperatures from 800°C to 950°C for 5 seconds. The luminescence spectra were measured from 0.7 to 1.6 eV at temperatures from 4-80 K and have features at 0.97, 1.17, 1.35, 1.40 and 1.5 eV. The band-to-acceptor luminescence shows the formation of Si acceptors, starting at an anneal temperature of about 850°C. The luminescence peak at 1,35 eV, attributed to As vacancy - acceptor complexes, is observed to increase in intensity with higher annealing temperatures. In contrast, the Ga vacancy-donor complex peak at 1,17 eV decreases in intensity. DLTS data show an increase in the density of deep levels and new levels not present in the unannealed material. Capacitance-voltage data find a reduction in carrier concentration, although type conversion is not observed even after annealing to 950°C.

Assessing the effect of H on the electronic properties of 4H-SiC

2021 ◽  
Author(s):  
Yuanchao Huang ◽  
Rong Wang ◽  
Yiqiang Zhang ◽  
Deren Yang ◽  
Xiaodong Pi
Keyword(s):  
Silicon Carbide ◽  
Electronic Properties ◽  
Thermal Annealing ◽  
Electron Concentration ◽  
Fermi Energy ◽  
Carrier Lifetime ◽  
Current Work ◽  
Defect States ◽  
Intrinsic Defects ◽  
Further Development

Abstract As a common impurity in 4H-silicon carbide (4H-SiC), hydrogen (H) may play a role in the tuning of the electronic properties of 4H-SiC. In this work, we systemically explore the effect of H on the electronic properties of both n-type and p-type 4H-SiC. The passivation of H for intrinsic defects such as carbon vacancies (VC) and silicon vacancies (VSi) in 4H-SiC is also evaluated. We find that interstitial H at the bonding center of the Si-C bond (Hi bc) and interstitial H at the tetrahedral center of Si (Hi Si-te) dominate the defect configurations of H in p-type and n-type 4H-SiC, respectively. For n-type 4H-SiC, the compensation of Hi Si-te is found to pin the Fermi energy and hinder the increase of electron concentration for highly N-doped 4H-SiC. The compensation of Hi bc is negligible compared to that of VC on the p-type doping of Al-doped 4H-SiC. We have further examined whether H can passivate VC and improve carrier lifetime in 4H-SiC. It turns out that nonequilibrium passivation of VC by H is effective to eliminate the defect states of VC, which enhances the carrier lifetime of moderately doped 4H-SiC. Regarding the quantum-qubit applications of 4H-SiC, we find that H can readily passivate VSi during the creation of VSi centers. Thermal annealing is needed to decompose the resulting VSi-nH (n=1~4) complexes and promote the uniformity of the photoluminescence of VSi arrays in 4H-SiC. The current work may inspire the further development of the impurity engineering of H in 4H-SiC.

Annealing Of Radiation Damage in Tungsten

1970 ◽  
Vol 28 ◽  
pp. 412-413
Author(s):  
Robert C. Rau ◽  
John Moteff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
Thermal Annealing ◽  
Neutron Fluence ◽  
Dislocation Loops ◽  
Defect Clusters ◽  
Polycrystalline Tungsten ◽  
Transmission Electron ◽  
Radiation Induced

Transmission electron microscopy has been used to study the thermal annealing of radiation induced defect clusters in polycrystalline tungsten. Specimens were taken from cylindrical tensile bars which had been irradiated to a fast (E > 1 MeV) neutron fluence of 4.2 × 1019 n/cm2 at 70°C, annealed for one hour at various temperatures in argon, and tensile tested at 240°C in helium. Foils from both the unstressed button heads and the reduced areas near the fracture were examined.Figure 1 shows typical microstructures in button head foils. In the unannealed condition, Fig. 1(a), a dispersion of fine dot clusters was present. Annealing at 435°C, Fig. 1(b), produced an apparent slight decrease in cluster concentration, but annealing at 740°C, Fig. 1(C), resulted in a noticeable densification of the clusters. Finally, annealing at 900°C and 1040°C, Figs. 1(d) and (e), caused a definite decrease in cluster concentration and led to the formation of resolvable dislocation loops.

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