Deposition amount effects on the microstructure of ion-beam-sputtering grown Mn_0.03Ge_0.97 quantum dots for spintronic applications

Here, a relative simpler and lower cost method, ion beam sputtering deposition was applied to fabricate diluted magnetic Mn_xGe_1−x quantum dots (QDs). The effects of Ge–Mn co-deposition amount on the morphology and crystallization of Mn_0.03Ge_0.97 QDs were investigated systematically by employing the atomic force microscopy and Raman spectroscopy techniques. It can be seen that the morphology, density, and crystallinity of Mn_0.03Ge_0.97 QDs exhibit unique evolution processes with the increase of Ge–Mn co-sputtering amount. The optimal deposition amount for realizing well size-uniform, large-aspect-ratio, and high-density QDs is also determined. The unique evolution route of diluted magnetic semiconductor QDs and the amount of co-sputtering are also discussed sufficiently. (paper)