Synthesis of highly mismatched alloys using ion implantation and pulsed laser melting

Highly mismatched alloys (HMAs) are dilute alloys whose fundamental properties are dramatically modified through the substitution of a relatively small fraction (up to ∼5%) of host atoms with a very different element. Specific examples are dilute III-V nitrides (e.g. GaN_xAs_1-x) and II-VI oxides (e.g. ZnO_xTe_1-x) in which the conduction bands are strongly modified by the anticrossing interaction between localized states of O or N and the extended states of the semiconductor matrix. Using a highly non-equilibrium method: the combination of ion implantation and pulsed laser melting (II-PLM) we have synthesized a wide variety of III-N_x-V_1-x and II-O_x-VI_1-x alloys with N or O content up to 2%. The structural and optical properties of these HMAs have been systematically investigated. In particular, we demonstrated that the Zn_1-yMn_yO_xTe_1-y dilute oxide is a multiband alloy that can be used for the realization of the single junction, high efficiency intermediate band solar cells.