Synthesis and optical properties of II-O-VI highly mismatched alloys

We have synthesized ternary and quaternary diluted II-VI oxides using the combination of O ion implantation and pulsed laser melting. CdOxTe1−x thin films with x up to 0.015, and the energy gap reduced by 150 meV were formed by O+-implantation in CdTe followed by pulsed laser melting. Quaternary Cd0.6Mn0.4OxTe1−x and Zn0.88Mn0.12OxTe1−x with mole fraction of incorporated O as high as 0.03 were also formed. The enhanced O incorporation in Mn-containing alloys is believed to be due to the formation of relatively strong Mn-O bonds. Optical transitions associated with the lower (E−) and upper (E+) conduction subbands resulting from the anticrossing interaction between the localized O states and the extended conduction states of the host are clearly observed in these quaternary diluted II-VI oxides. These alloys fulfill the criteria for a multiband semiconductor that has been proposed as a material for making high efficiency, single-junction solar cells.