Donor-Acceptor Pair Luminescence in 4H-SiC Doped with Nitrogen and Aluminum

I. G. Ivanov et al., "Donor-Acceptor Pair Luminescence in 4H-SiC Doped with Nitrogen and Aluminum", Materials Science Forum, Vols. 433-436, pp. 321-324, 2003

Online since:

September 2003

Authors:

Ivan G. Ivanov, Alexsandre Ellison, Erik Janzén

Keywords:

Donor-Acceptor Pair Recombination, Ionization Energy, Luminescence

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References

[1] L. Patrick: Phys. Rev. Lett. Vol. 21 (1968), p.1685.

[2] For a review, see A. M. Stoneham: Theory of Defects in Solids: Electronic Structure of Defects in Insulators and Semiconductors (Clarendon Press - Oxford, England 1975), Chapter 25.

[3] S.H. Hagen A.W.C. van Kemenade and J.A.W. van Der Does De Bye: J. Lumin. Vol. 8(1973), p.18.

[4] M. Ikeda, H. Matsunami, and T. Tanaka: Phys. Rev. B Vol. 22 (1980), p.2842.

[5] P. J. Dean and L. Patrick: Phys. Rev. B Vol. 2 (1970), p.1888.

[6] I. G. Ivanov, B. Magnusson and E. Janzén, to be published.

[7] I. G. Ivanov, J. Zhang, L. Storasta and E. Janzén, Proc. of thr International Conference on Silicon Carbide and Related Materials 2001 (Trans Tech Publications, Switzerland 2002), p.613.

[8] For a recent review, see S. Greulich-Weber, Phys. Stat. Sol. (a) Vol. 162 (1997).

Paper TitlePages

Photoluminescence Excitation Spectroscopy on the Donor-Acceptor Pair Luminescence in 4H and 6H SiC

Authors: Ivan G. Ivanov, Erik Janzén

585

The Optical Admittance Spectroscopy of the Vanadium Donor and Acceptor Levels in Semi-Insulating 4H-SiC and 6H-SiC

Authors: Won Woo Lee, Mary Ellen Zvanut

Abstract: The purpose of this study is to determine the vanadium defect levels in semi-insulating 4H-SiC and 6H-SiC using optical admittance spectroscopy (OAS). OAS data show several distinct peaks for the vanadium-doped SI 4H-SiC and 6H-SiC. Comparison of the data for the two polytypes suggests that peaks at 0.67 ± 0.02 eV and 0.70 ± 0.02 eV in 6H substrates and 0.75 ± 0.02 eV in 4H substrates are related to V3+/4+ levels at the cubic sites. A peak at 0.87 ± 0.02 eV in the 6H sample is assigned to the same defect level at the hexagonal site and the associated transition in 4H was observed at 0.94 ± 0.02 eV in our spectra. The donor levels are thought to be related to peaks at 1.94 ± 0.05 eV and 1.87 ± 0.05 eV in 4H and 6H samples, respectively. The differences between the values obtained from the optical admittance measurements and those reported in the literature are attributed to thermal relaxation and/or contributions from defect complexes.

647

Deep Levels Responsible for Semi-Insulating Behavior in Vanadium-Doped 4H-SiC Substrates

Authors: Nguyen Tien Son, Patrick Carlsson, Andreas Gällström, Björn Magnusson, Erik Janzén

Abstract: Semi-insulating (SI) 4H-SiC substrates doped with vanadium (V) in the range 5.5×1015 –1.1×1017 cm–3 were studied by electron paramagnetic resonance. We show that only in heavily V-doped 4H-SiC vanadium is responsible for the SI behavior, whereas in moderate V-doped substrates with the V concentration comparable or slightly higher than that of the shallow N donor or B acceptor, the SI properties are thermally unstable and determined by intrinsic defects. The results show that the commonly observed thermal activation energy Ea~1.1 eV in V-doped 4H-SiC, which was previously assigned to the single acceptor V4+/3+ level, may be related to deep levels of the carbon vacancy. Carrier compensation processes involving deep levels of V and intrinsic defects are discussed and possible thermal activation energies are suggested.

401

Reduction in Majority-Carrier Concentration in Lightly-Doped 4H-SiC Epilayers by Electron Irradiation

Authors: Hideharu Matsuura, Hideki Yanagisawa, Kozo Nishino, Takunori Nojiri, Shinobu Onoda, Takeshi Ohshima

Abstract: The mechanisms for the reduction in the hole concentration in lightly Al-doped p-type 4H-SiC epilayers by electron irradiation as well as in the electron concentration in lightly N-doped n-type 4H-SiC epilayers by electron irradiation are investigated. In the p-type 4H-SiC epilayers, the temperature dependence of the hole concentration, , is not changed by 100 keV electron irradiation, while the is decreased by 150 keV electron irradiation. The density of Al acceptors with energy level eV decreases with increasing fluence of 150 keV electrons, whereas the density of deep acceptors with energy level eV increases. In the n-type 4H-SiC epilayers, the temperature dependence of the electron concentration, , is decreased by 200 keV electron irradiation. The density of N donors located at hexagonal C-sublattice sites decreases significantly with increasing fluence of 200 keV electrons, whereas the density of N donors located at cubic C-sublattice site decreases slightly.

181

Defect Composition in Acceptor Doped ZnO Quantum Structures

Authors: Tamar Tchelidze, Tamaz Kereselidze

Abstract: We investigated defect composition in ZnO quantum structures – quantum wells and nanowires doped with Ag impurity. We investigated the influence of space and dielectric confinement on ionization energies of acceptor and compensation donor centers. These calculations show that in nanowire there is a optimal range of radius where the creation of ionized donors compensating hole conductivity, and consequently, improvement of hole conductivity, is possible to suppress.

391