Device Research Laboratory, Department of Electrical Engineering, University of California, Los Angeles, CA 90095, USA.
Nanotechnology. 2010 Dec 17;21(50):505704. doi: 10.1088/0957-4484/21/50/505704. Epub 2010 Nov 22.
In this study, we report on the formation of a single-crystalline Ni(2)Ge/Ge/Ni(2)Ge nanowire heterostructure and its field effect characteristics by controlled reaction between a supercritical fluid-liquid-solid (SFLS) synthesized Ge nanowire and Ni metal contacts. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal a wide temperature range to convert the Ge nanowire to single-crystalline Ni(2)Ge by a thermal diffusion process. The maximum current density of the fully germanide Ni(2)Ge nanowires exceeds 3.5 × 10(7) A cm(-2), and the resistivity is about 88 μΩ cm. The in situ reaction examined by TEM shows atomically sharp interfaces for the Ni(2)Ge/Ge/Ni(2)Ge heterostructure. The interface epitaxial relationships are determined to be [Formula: see text] and [Formula: see text]. Back-gate field effect transistors (FETs) were also fabricated using this low resistivity Ni(2)Ge as source/drain contacts. Electrical measurements show a good p-type FET behavior with an on/off ratio over 10(3) and a one order of magnitude improvement in hole mobility from that of SFLS-synthesized Ge nanowire.
在这项研究中，我们通过控制超临界流体-液体-固体（SFLS）合成的 Ge 纳米线与 Ni 金属接触之间的反应，报告了单晶 Ni(2)Ge/Ge/Ni(2)Ge 纳米线异质结构的形成及其场效应特性。扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究表明，在很大的温度范围内，通过热扩散过程可以将 Ge 纳米线转化为单晶 Ni(2)Ge。完全锗化的 Ni(2)Ge 纳米线的最大电流密度超过 3.5×10(7)A cm(-2)，电阻率约为 88μΩ cm。通过 TEM 进行的原位反应表明，Ni(2)Ge/Ge/Ni(2)Ge 异质结构具有原子级锐利的界面。确定了界面外延关系为[Formula: see text]和[Formula: see text]。还使用这种低电阻率的 Ni(2)Ge 作为源/漏接触制造了背栅场效应晶体管（FET）。电测量显示出良好的 p 型 FET 行为，开关比超过 10(3)，并且空穴迁移率比 SFLS 合成的 Ge 纳米线提高了一个数量级。
