Energy Levels of Point Defects in Perovskite Oxides

1994 ◽  
Vol 361 ◽  
Author(s):  
J. Robertson ◽  
W. L. Warren
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Band Gap ◽  
Point Defects ◽  
Energy Levels ◽  
Perovskite Oxides ◽  
Atomic Electron ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
Trapped Electron

ABSTRACTThe band structure and energy levels of defects in BaTi3, PbTiO3 and PbZrO3 are calculated and compared. The band gap of Pb(Zr,Ti)O3 varies little because the band edges are formed of Pb 6s and 6p states. The charged Ti and O vacancies are found to be shallow. Transition metal impurities at the B site are found to give rise to numerous charge states because of their high intra-atomic electron repulsion. The levels of Cr4+, Fe4+ and Co4+ lie near midgap. Ti3+ trapped electron centers become deep at higher Zr contents in PZT.

Transition Metal Impurities in Silicon

1982 ◽  
Vol 14 ◽  
Author(s):  
Eicke R. Weber ◽  
Norbert Wifhl
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
High Temperatures ◽  
Energy Levels ◽  
Pair Formation ◽  
Interstitial Solution ◽  
3D Metals ◽  
Metal Impurities ◽  
Transition Metal Impurities ◽  
3D Elements

ABSTRACTThe properties of transition metals in silicon are reviewed, emphasizing those observations which allow conclusions to be drawn with respect to microscopic defect models. 3d metals diffuse interstitially into silicon and stay predominantly in these sites at high temperatures. 3d elements lighter than Co can be quenched into these interstitial sites, giving rise to well-established energy levels. First theoretic calculations for these ions yield promising results. Co, Ni and Cu vanish out of the interstitial solution during quenching; an appreciable fraction of Cu may form pairs. The understanding of 4d and 5d metals in silicon is much less advanced at present, even for the technologically important elements Au and Pt. Some observations indicate that for Au and Pt pair formation might as well be important.

Electronic-Structure Calculation of 3d Transition-Metal Point Defects in Silicon

1985 ◽  
Vol 46 ◽  
Author(s):  
Franz Beeler ◽  
Ole K. Andersen ◽  
Matthias Scheffler
Keyword(s):  
Electronic Structure ◽  
Transition Metal ◽  
Point Defects ◽  
Ground States ◽  
Structure Calculation ◽  
Electronic Structure Calculation ◽  
Iron Group ◽  
Metal Impurities ◽  
Donor And Acceptor ◽  
Transition Metal Impurities

AbstractThe states of lowest energy have been calculated for iron-group (3d) transition-metal impurities in silicon. The donor and acceptor levels reproduce all experimentally observed transitions and trends. The theory predicts that the ground states of the early 3d interstitials and late 3d substitutionals have low spin. This is in conflict with the generally accepted model of Ludwig and Woodbury, if applied to these impurities, but not with existing experiments.

Transition-Metal Impurity Luminescence in GaAs and its Application to Material Characterization

1995 ◽  
Vol 378 ◽  
Author(s):  
T. Nishino
Keyword(s):  
Transition Metal ◽  
Near Infrared ◽  
Energy Levels ◽  
Local Strain ◽  
Infrared Region ◽  
Luminescence Line ◽  
Metal Impurities ◽  
Transition Metal Impurity ◽  
Transition Metal Impurities

AbstractA number of sharp characteristic luminescence lines has been observed for GaAs doped with 3d transition-metal impurities in the near-infrared region, the origin being attributed to the zero-phonon intracenter transitions between the energy levels of the metal ions split by the crystal field of the GaAs lattice. It is also known that these luminescence lines are very sensitive to the surrounding field of the transition-metal impurities. The luminescence of Cr-doped GaAs has been most extensively studied, the spectrum revealing a very sharp luminescence line at 0.839 eV. In this paper we review the results on the successful applications of this Cr-related luminescence line to characterization of in-depth profiles of arsenic vacancy in thermally annealed GaAs, local strain field in In-doped GaAs and interface stress at heterostructures grown on Cr-doped GaAs substrate.

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