Characterization of Defects in N-Type 6H-SiC Single Crystals by Optical Admittance Spectroscopy

1993 ◽  
Vol 325 ◽  
Author(s):  
A.O. Evwaraye ◽  
S.R. Smith ◽  
W.C. Mitchel
Keyword(s):  
Single Crystals ◽  
Admittance Spectroscopy ◽  
Donor Atom ◽  
Deep Defect ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
Defect Levels ◽  
First Time ◽  
Type Conduction

AbstractOptical admittance spectroscopy is a technique for measuring the conductance and capacitance of a junction under illumination as a function of the wavelength of the light and the frequency of the measuring AC signal. For the first time, this technique is applied to characterize deep defect levels in 6H-SiC:N. Nitrogen is a donor atom in 6H-SiC which substitutes for carbon in three inequivalent sites (h, kl, k2). giving rise to n-type conduction. Deep defect levels attributible to transition metal impurities have been identified in 6H-SiC:N by optical admittance spectroscopy.

Characterization of Defects in N-Type 6H-SiC Single Crystals by Optical Admittance Spectroscopy

1994 ◽  
Vol 339 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel
Keyword(s):  
Transition Metal ◽  
Single Crystals ◽  
Admittance Spectroscopy ◽  
Donor Atom ◽  
Deep Defect ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
Defect Levels ◽  
Type Conduction

ABSTRACTOptical admittance spectroscopy is a technique for measuring the conductance and capacitance of a junction under illumination as a function of the wavelength of the light and the frequency of the measuring AC signal. This technique has been applied to characterize deep defect levels in 6H-SiC:N. Nitrogen is a donor atom in 6H-SiC which substitutes for carbon in three inequivalent sites (h, k1, k2). giving rise to n-type conduction. Deep defect levels attributable to transition metal impurities have also been identified in 6H-SiC:N. We have examined persistent photoconductance in this material by optical admittance spectroscopy.

Characterization of deep defect levels in amorphous selenium by optical methods

1987 ◽  
Vol 97-98 ◽  
pp. 663-666 ◽  
Author(s):  
Shunji Imamura ◽  
Yoshihiko Kanemitsu ◽  
Tomio Hayano ◽  
Takashi Kitamura
Keyword(s):  
Amorphous Selenium ◽  
Optical Methods ◽  
Deep Defect ◽  
Defect Levels

Deep defect levels in CuInSe2 single crystals using DLTS, MCTS and photoacoustic spectroscopy

2019 ◽  
Vol 99 ◽  
pp. 172-177 ◽  
Author(s):  
Azidine Benhenni ◽  
Fatima Zohra Satour ◽  
Ahmed Zouaoui ◽  
Ameur Zegadi
Keyword(s):  
Single Crystals ◽  
Photoacoustic Spectroscopy ◽  
Deep Defect ◽  
Defect Levels

Characterization of defect levels in β-Ga2O3 single crystals doped with tantalum

CrystEngComm ◽  
2021 ◽  
Vol 23 (15) ◽  
pp. 2835-2841
Author(s):  
Haoyue Liu ◽  
Naiji Zhang ◽  
Junhua Yin ◽  
Changtai Xia ◽  
Zhe Chuan Feng ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Defect Characterization ◽  
Floating Zone ◽  
Zone Method ◽  
Floating Zone Method ◽  
Defect Levels

Optical properties and defect characterization of Ta-doped β-Ga2O3 single crystals grown by the optical floating zone method.

Effect of C/B Sequential Implantation on the B Acceptors in 4H-SiC

2000 ◽  
Vol 640 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Tetsu Kachi ◽  
Hiroshi Tadano ◽  
Rajesh Kumar Malhan
Keyword(s):  
Ionization Energy ◽  
Hole Concentration ◽  
Deep Levels ◽  
Admittance Spectroscopy ◽  
Deep Defect ◽  
Complex Defect ◽  
Rich Condition ◽  
Defect Levels ◽  
Expected Increase

ABSTRACTWe have systematically investigated the effect of C/B sequential implantation on the B-related acceptors and deep levels in 4H-SiC using thermal admittance spectroscopy. With increasing concentration of co-implanted C, the density of deep levels was found to start decreasing and to be completely suppressed for the C and B ratio of 1:1. Moreover, the density and ionization energy of B acceptors were seen to start increasing and lowering, respectively, with increasing C concentration. However, we found that excess C-content leads to the formation of a new complex defect. The C-V results also support the expected increase in the total hole concentration with increasing concentration of the co-implanted C-atoms, which is followed by a decrease in the concentration under C-rich condition. This is in reasonable agreements with the behavior of the B acceptors and deep defect levels. Therefore, the concentration of co-implanted C-atoms is considered to be very sensitive to the formation of the B acceptor levels.

Synthesis and powder diffraction analysis of tri-rubidium penta-tantalum oxide, Rb3Ta5O14, with novel three-dimensionally nanostructured Rb-bearing channels

2003 ◽  
Vol 18 (1) ◽  
pp. 2-6
Author(s):  
A. Oono ◽  
M. Yashima ◽  
D. du Boulay ◽  
N. Ishizawa ◽  
A. Saiki ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Single Crystals ◽  
Powder Diffraction ◽  
Raw Materials ◽  
Tantalum Oxide ◽  
Powder Pattern ◽  
Synthesis And Characterization ◽  
First Time

The powder pattern of Rb3Ta5O14 is reported here for the first time. Single crystals of Rb3Ta5O14 of 0.1–0.2 mm in size were grown using a RbCl flux at 1100 °C. The Rb3Ta5O14 powders were synthesized at 1200 °C by firing the Rb2CO3 and Ta2O5 raw materials with starting Rb/Ta ratios ranging from 0.450 to 0.800. The products with Rb/Ta ratios between 0.550 and 0.633 contained almost pure Rb3Ta5O14 with Rb/Ta ratio of 0.600, while those with Rb/Ta ratio larger than 0.677 also contained the α form of Rb4Ta6O17 with the Rb/Ta ratio of 0.677. Past studies of the synthesis and characterization of Rb4Ta6O17 should be carefully examined in the light of possible coexistence with Rb3Ta5O14, because the former structure has not been completely solved, and thus the powder pattern is inaccurate, while the presence of the latter had not been known until the present study.

The Effect of Annealing on High-resistivity and Semi-insulating 4H-SiC

2002 ◽  
Vol 742 ◽  
Author(s):  
S. R. Smith ◽  
A. O. Evwaraye ◽  
W. C. Mitchel
Keyword(s):  
Transition Metal ◽  
Thermal Oxidation ◽  
Thermal Annealing ◽  
Deep Levels ◽  
High Resistivity ◽  
Admittance Spectroscopy ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
Before And After

ABSTRACTWe have examined specimens of high-resistivity, and semi-insulating, 4H-SiC before and after thermal annealing at 1600 °C, using Optical Admittance Spectroscopy. We have found enhanced ultraviolet response in most specimens. Enhanced activation of previously undetected V impurities has also been observed. Peaks believed to be attributable to complex V-related defects were greatly reduced by annealing. The annealing was in addition to a thermal oxidation at 1150 °C for 4 hours. The purpose of the oxidation was to remove surface-related deep levels known to be present in polished SiC. Transition metal impurities in these bulk specimens were quantified by SIMS. In specimens where Ti was not detected by SIMS, no further activation of Ti centers was detected by Optical Admittance Spectroscopy.

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