Lifetime recovery in ultrahighly titanium-doped silicon for the implementation of an intermediate band material

The doping of conventional semiconductors with deep level (DL) centers has been proposed to synthesize intermediate band materials. A recent fundamental study of the nonradiative recombination (NRR) mechanisms predicts the suppression of the NRR for ultrahigh DL dilutions as a result of the delocalization of the impurity electron wave functions. Carrier lifetime measurements on Si wafers doped with Ti in the 1020–1021 cm−3 concentration range show an increase in the lifetime, in agreement with the NRR suppression predicted and contrary to the classic understanding of DL action.