Development of inorganic/organic-based diluted magnetic semiconductors for spin-polarized transistors

毫无疑问，在过去的30年里，半导体电子技术的进步极大地影响了我们的生活水平。这种快速增长是由各种电子设备的规模化推动的。然而，最近有人预测，在不久的将来，传统的半导体电子学将面临根本性的局限性。当器件尺寸小于10nm（目前为65nm）时，由于电子的量子行为，可靠的信息处理是不可能的。为了克服这一问题并取得进一步的进展，利用自旋相关和电荷相关电流的自旋电子学（或自旋电子学）已被广泛利用，作为仅依赖于电流二进制状态（1位或0位）的半导体技术的有前途的替代方案。我提出这个研究计划是为了生产新的铁磁性半导体，这是自旋电子学的关键元素。自旋是电子的一种固有性质，它可以表现为两种可区分的磁能状态（自旋向上和自旋向下）。传统的半导体电子学只利用了电荷自由度（正空穴和负电子），而没有考虑载流子的自旋特性，因为目前可用的半导体材料中缺乏铁磁性。因此，自旋电子学技术需要具有铁磁性的新型半导体，从而能够产生和控制自旋极化电子电流，并在现有半导体结构中保持长时间和距离的自旋相干性。将磁性结合到有机和无机基半导体材料中，将尝试使用磁性杂质掺杂方法。铁磁半导体及其传输自旋极化电子的能力将有助于实现未来的自旋电子器件，包括自旋晶体管、磁存储器、在磁场和电场中工作的逻辑电路。

There is no doubt that progress in the semiconductor electronics has impacted immensely on our standard of living in the past 30 years. This rapid growth has been driven by scaling a variety of electronic devices. However, it was recently predicted that traditional semiconductor electronics will face fundamental limitations in near future. When the device scaling goes below around 10 nm (65 nm at present), a reliable information processing is known to be impossible due to the quantum behavior of electrons. To overcome this problem and attain further progress, spin-electronics (or spintronics) utilizing both spin-dependent and charge-dependent electric currents has been intensively exploited as a promising alternative to the semiconductor technology relying only on the binary states of electric current (bit of 1 or 0). I am proposing this research program to produce new ferromagnetic semiconductors which is a key element in spin-electronics. The spin is an intrinsic property of electrons which can be manifested as two distinguishable magnetic-energy states (spin-up and spin-down). The conventional semiconductor-based electronics have utilized only the charge degree of freedom (positive holes and negative electrons) without considering the spin properties of charge carriers because ferromagnetism is absent in currently available semiconducting materials. Therefore spintronics technology requires new semiconductors which show ferromagnetic behavior and thus allow a current of spin-polarized electrons to be generated and controlled, and preserve the spin-coherence over long time and distance in an existing semiconductor structure. The incorporation of magnetism into organic-and inorganic-based semiconducting materials will be attempted using the magnetic-impurity doping method. This work on ferromagnetic semiconductors and their abilities to transport the spin-polarized electrons will facilitate the realization of future spintronic devices, including spin-transistors, magnetic memory, logic-circuits working both in magnetic and electric fields.