Ferromagnetic germanide in Ge nanowire transistors for spintronics application

Jianshi Tang, Chiu Yen Wang, Min Hsiu Hung, Xiaowei Jiang, Li Te Chang, Liang He, Pei Hsuan Liu, Hong Jie Yang, Hsing Yu Tuan, Lih Juann Chen, Kang L. Wang

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61 Citations (Scopus)


To explore spintronics applications for Ge nanowire heterostructures formed by thermal annealing, it is critical to develop a ferromagnetic germanide with high Curie temperature and take advantage of the high-quality interface between Ge and the formed ferromagnetic germanide. In this work, we report, for the first time, the formation and characterization of Mn 5Ge 3/Ge/Mn 5Ge 3 nanowire transistors, in which the room-temperature ferromagnetic germanide was found through the solid-state reaction between a single-crystalline Ge nanowire and Mn contact pads upon thermal annealing. The atomically clean interface between Mn 5Ge 3 and Ge with a relatively small lattice mismatch of 10.6% indicates that Mn 5Ge 3 is a high-quality ferromagnetic contact to Ge. Temperature-dependent I-V measurements on the Mn 5Ge 3/Ge/Mn 5Ge 3 nanowire heterostructure reveal a Schottky barrier height of 0.25 eV for the Mn 5Ge 3 contact to p-type Ge. The Ge nanowire field-effect transistors built on the Mn 5Ge 3/Ge/Mn 5Ge 3 heterostructure exhibit a high-performance p-type behavior with a current on/off ratio close to 10 5, and a hole mobility of 150-200 cm 2/(V s). Temperature-dependent resistance of a fully germanided Mn 5Ge 3 nanowire shows a clear transition behavior near the Curie temperature of Mn 5Ge 3 at about 300 K. Our findings of the high-quality room-temperature ferromagnetic Mn 5Ge 3 contact represent a promising step toward electrical spin injection into Ge nanowires and thus the realization of high-efficiency spintronic devices for room-temperature applications.

Original languageEnglish
Pages (from-to)5710-5717
Number of pages8
JournalACS nano
Issue number6
Publication statusPublished - 2012 Jun 26

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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