Open AccessTheoretical analysis of cascade levels forming in SrTiO3
Author(s) -
Ruizhi Zhang,
Chunlei Wang,
Jichao Li,
Mei Liang-Mo
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.7162
Subject(s) - cascade , quasi fermi level , semimetal , doping , condensed matter physics , materials science , electronic band structure , electron , direct and indirect band gaps , thermal conduction , band gap , transition point , physics , chemistry , quantum mechanics , chromatography , mechanics , composite material
The possibility of forming cascading energy levels in SrTiO3 by doping Bi and Cu as an example is analyzed by using the density-functional-theory based first principles calculations of the electronic structure. The results show that both Bi doping and Cu doping can introduce a defect level in the forbidden bandand Co-doping of Bi and Cu can introduce two defect levels in the forbidden band. Electrons at the top of valence band can transit to the bottom of conduction band through a cascade transition process. Using the nonradiative transition modelwe point out that the probability of electronic transition from the valence band to the conduction band through a cascade transition is much higher than that of direct transition from the valence band to the conduction band. The cascade transitions can effectively increase the carrier concentration in the conduction band.