Ferromagnetic germanide in Ge nanowire transistors for spintronics application.
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(5)Ge(3)/Ge/Mn(5)Ge(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(5)Ge(3) and Ge with a relatively small lattice mismatch of 10.6% indicates that Mn(5)Ge(3) is a high-quality ferromagnetic contact to Ge. Temperature-dependent I-V measurements on the Mn(5)Ge(3)/Ge/Mn(5)Ge(3) nanowire heterostructure reveal a Schottky barrier height of 0.25 eV for the Mn(5)Ge(3) contact to p-type Ge. The Ge nanowire field-effect transistors built on the Mn(5)Ge(3)/Ge/Mn(5)Ge(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(5)Ge(3) nanowire shows a clear transition behavior near the Curie temperature of Mn(5)Ge(3) at about 300 K. Our findings of the high-quality room-temperature ferromagnetic Mn(5)Ge(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.
Device Research Laboratory, Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA.
Jianshi
J
Tang
Chiu-Yen
CY
Wang
Min-Hsiu
MH
Hung
Xiaowei
X
Jiang
Li-Te
LT
Chang
Liang
L
He
Pei-Hsuan
PH
Liu
Hong-Jie
HJ
Yang
Hsing-Yu
HY
Tuan
Lih-Juann
LJ
Chen
Kang L
KL
Wang
D004867:Equipment Design; D019544:Equipment Failure Analysis; D005857:Germanium / Q000737:chemistry*; D059346:Magnets; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D014173:Transistors, Electronic
D005857:Germanium