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Using density functional theory, we have analyzed the ways and means of improving the minority carrier lifetime (MCL) by calculating the band structure dependent quantities contributing to the MCL. We have computationally modeled silicon doped with different elements like B, C, N, O, P, Ti, Fe, Ga, Ge, As, In, Sn, Sb, and Pt and looked at the effect of doping on MCL. In co-doping, the systems Si-B-Ga, Si-B-Ge, Si-B-2Ge, Si-B-Pt, Si-Ga-Ge, Si-Ga-2Ge, and Si-Ga-Pt are investigated. From our calculation, it is found that by doping and co-doping of Si with suitable elements having “s” and “p” electrons, there is a decrease in the recombination activity. The predicted effective minority carrier lifetime indicates the possibility of significant improvements. Based on the above studies, it is now maybe possible, with suitable choice of dopant and co-dopant material, to arrive at part of a standard production process for solar grade Si material. [ABSTRACT FROM AUTHOR]

Using first principles method we elaborately discuss the magnetic, elastic and optical properties of pure, Zn and O vacant ZnO 2 . It is found that the electronic structure and band gap of ZnO 2 is not sensitive to the active on-site Coulomb interaction term U d , but found to be depending on the term U p . The role of orbitals subject to the correlation is thus completely opposite for the case of ZnO 2 in respect of ZnO. Interestingly, the Zn vacancy converts ZnO 2 as “ d 0 magnet”. Indeed, our analysis show that, Zn vacancy transmuted O 2 2− state into O 2 δ +2− state, indicating the partially filled π ∗ states are the governing reason for the d 0 magnetism. Both HSE06 and PBE0 functional confirm the same. The similar phenomena has been observed for other peroxide materials XO 2 (X = Mg, Ca, Sr, Ba) studied here. Our results suggest that this class of materials can be studied further to exploit its potential in spintronic devices. Further the elastic properties have been estimated for pure ZnO 2 at different pressures and for Zn and O vacant ZnO 2 to know the stability of the system. Zn vacancy in ZnO 2 also tunes optical properties, indicating its potential application in other areas. [ABSTRACT FROM AUTHOR]