MBE growth and ordering of ferromagnetic MnGe nanocrystals on a nanopatterned insulating layer

Abstract

This paper presents a novel methodology for growing highly ordered arrays of self-assembled manganese-germanium (MnGe) nanocrystals (NCs) on an insulating SiO₂ layer. This approach utilizes solid-state dewetting of thin MnGe films, deposited by molecular beam epitaxy (MBE), onto a nanopatterned SiO₂ surface created via electron beam lithography (EBL). Detailed analysis of morphology, structure, and magnetic properties reveals key attributes of these MnGe NCs: a Curie temperature exceeding room temperature (325 K), high purity, defined shape and crystalline structure, high density, and a remarkably narrow size distribution. Moreover, these NCs exhibit precise and tunable ordering based on the specific patterns etched into the SiO₂ surface, showcasing the effectiveness of combining surface nanostructuring with solid-state dewetting of MnGe layers. These results represent a significant advancement in magnetic semiconductor nanocrystal growth, with promising implications for applications in spintronic and optoelectronic devices.