The scaling effects of the Ge₈Sb₉₂ thin films on the phase change behavior, thermal properties, phase structure, crystallization mechanism and electrical switching characteristics of phase change memory were systematically investigated.

The effects of a titanium dopant on the phase transition behavior and crystallization mechanism of Ge₈Sb₉₂ films were systematically investigated.

This review highlights recent progress in utilizing iron oxide nanoparticles (IONPs) as a safer alternative to gadolinium-based contrast agents (GBCAs) for magnetic resonance imaging (MRI). It consolidates findings from multiple studies, discussing current T₁ contrast agents (CAs), the synthesis techniques for IONPs, the theoretical principles for designing IONP-based MRI CAs, and the key factors that impact their T₁ contrast efficacy, such as nanoparticle size, morphology, surface modifications, valence states, and oxygen vacancies. Furthermore, we summarize current strategies to achieve IONP-based responsive CAs, including self-assembly/disassembly and distance adjustment. This review also evaluates the biocompatibility, organ accumulation, and clearance pathways of IONPs for clinical applications. Finally, the challenges associated with the clinical translation of IONP-based T₁ CAs are included.

Effects of oxygen incorporation on the crystallization characteristics and crystal structure of Ge ₈ Sb ₉₂ films were systematically investigated. The amorphous-to-crystalline transition was studied by in situ resistance measurement. The thermal stability, electrical resistance and band gap of Ge ₈ Sb ₉₂ material increase significantly by the addition of oxygen. X-ray diffraction, transmission electron microscopy and x-ray photoelectron spectroscopy illustrate that a small amount of oxygen dopant can inhibit the grain growth and limit the grain size because of the formation of Ge and Sb oxide. Atomic force microscopy and x-ray reflectivity results indicate that the film surface becomes smoother and the film thickness change becomes smaller after oxygen doping. Phase change memory cells based on oxygen-doped Ge ₈ Sb ₉₂ film were fabricated to evaluate the electrical properties as well. All the results demonstrate that suitable incorporation of oxygen is an effective way to enhance the comprehensive performance of Ge ₈ Sb ₉₂ thin films for phase change memory application.

Effects of the titanium dopant on the physical properties and structure of SbSe thin films were systematically investigated by experiments and first-principles calculations. The amorphous-to-polycrystalline transformation induced by heat was examined by in situ electrical resistance measurements. With the incorporation of titanium atoms, both the crystallization temperature and electrical resistance increase, revealing the improvement of the amorphous thermal stability and programing energy consumption. X-ray diffraction, transmission electron microscopy, and density functional theory calculations illustrate that a small amount of titanium dopant can inhibit the grain growth and refine the crystal size. The shift of Raman modes associated Sb upon the crystallization was observed. X-ray reflectivity and atomic force microscopy results prove the smaller volume fluctuation and the smoother surface morphology, meaning the better interfacial property and reliability of titanium-doped SbSe materials. Phase change memory cells based on titanium-doped antimony-selenium were fabricated to evaluate the electrical performance as well. All these results indicate that the suitable incorporation of the titanium element will be an effective method to optimize the physical properties and tune the structure of the SbSe phase change material.

Titanium-doped SnSb₄ phase-change thin film has been experimentally investigated for phase-change random access memory (PCRAM) use.