紅熒烯中介層對Co2Ni/矽(100)薄膜磁特性、結構之影響

Abstract

有機半導體以其獨特的應用潛力和製造優勢，激發了學界對其大規模研究的熱情，被廣泛認為是下一代半導體技術的關鍵。紅熒烯是一種具有高載流子遷移率和優異光電性能的有機半導體材料，廣泛應用於場效應電晶體（field-effect transistor, FET）、有機光電元件和有機發光二極體（organic light-emitting diodes, OLED）等領域。鈷鎳合金因其在磁性材料中的優越性，如低矯頑力和可調的磁異向性，成為廣泛研究和應用的重要對象，這些合金的性質可以透過調整鈷和鎳的比例來優化。本研究深入探討了Co2Ni薄膜在矽基板和紅熒烯界面上的磁特性及結構。包括利用磁光科爾效應、科爾顯微鏡和鐵磁共振技術來觀察磁特性的變化，以及原子力顯微鏡、X光繞射、X光反射率和X光光電子能譜來分析薄膜的表面形貌、晶體結構、界面粗糙度和化學組成。研究結果表明，Co2Ni /矽(100)系統矯頑力沒有超過50 Oe，隨著紅熒烯的引入，Co2Ni薄膜矯頑力上升、改變磁域尺寸大小和表面形貌更加蜿蜒，以及提升表面粗糙度。 Co2Ni薄膜成長顯示薄膜呈現fcc結構(111)方向奈米晶生長，晶粒大小為幾個奈米，而Co2Ni薄膜深度分析確認了薄膜中鈷與鎳的均勻成分成長。紅熒烯引入導致電子能階偏移約為0.1 eV，顯示對紅熒烯中介層對於鐵磁層電子結構有顯著影響。紅熒烯中介層效應對磁性合金薄膜成長應用的潛在意義，特別是在提高矯頑力、方正度以及改變磁域結構對於合金鐵磁性薄膜製程有重要角色。Organic semiconductors, known for their unique application potential and manufacturing advantages, have sparked considerable interest in academia and are widely regarded as key components of next-generation semiconductor technology. Rubrene, an organic semiconductor material with high carrier mobility and excellent optoelectronic properties, is extensively used in applications such as field-effect transistors (FET), organic photovoltaic devices, and organic light-emitting diodes (OLED). Cobalt-nickel alloys, valued in magnetic materials for their advantages such as low coercivity and tunable magnetic anisotropy, have been the focus of research and applications, with their properties optimized by adjusting the cobalt-to-nickel ratio.This study explores the magnetic properties and structure of Co₂Ni films at the silicon substrate and rubrene interface. Techniques including magneto-optical Kerr effect(MOKE), Kerr microscopy(KM), and ferromagnetic resonance were used to observe changes in magnetic properties, while atomic force microscopy, x-ray diffraction, x-ray reflectivity, and x-ray photoelectron spectroscopy were employed to analyze surface morphology, crystal structure, interface roughness, and chemical composition. The results show that the coercivity of the Co₂Ni/Si(100) system remains below 50 Oe. With the introduction of rubrene, the coercivity of the Co₂Ni film increases, the magnetic domain size changes, the surface morphology becomes more undulating, and the surface roughness is enhanced. The growth of Co₂Ni films indicates polycrystalline growth with a preference for the (111) orientation of the face-centered cubic (fcc) structure, with grain sizes of a few nanometers. Depth analysis confirmed a uniform distribution of cobalt and nickel within the film. The introduction of rubrene causes an energy level shift of approximately 0.1 eV, highlighting a significant influence of the rubrene interlayer on the electronic structure of the ferromagnetic layer. The effects of the rubrene interlayer hold potential implications for the growth of magnetic alloy films, particularly in enhancing coercivity, squareness, and modifying magnetic domain structures, which play a crucial role in the processing of ferromagnetic alloy thin films.