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.

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.

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