E center in silicon has a donor level in the band gap.
Larsen AN, Mesli A, Nielsen KB, Nielsen HK, Dobaczewski L, Adey J, Jones R, Palmer DW, Briddon PR, Oberg S.
Larsen AN, et al. Among authors: mesli a.
Phys Rev Lett. 2006 Sep 8;97(10):106402. doi: 10.1103/PhysRevLett.97.106402. Epub 2006 Sep 7.
Phys Rev Lett. 2006.
PMID: 17025833