Nanomaterials (Mar 2024)

Characterization of Mn<sub>5</sub>Ge<sub>3</sub> Contacts on a Shallow Ge/SiGe Heterostructure

  • Troy A. Hutchins-Delgado,
  • Sadhvikas J. Addamane,
  • Ping Lu,
  • Tzu-Ming Lu

DOI
https://doi.org/10.3390/nano14060539
Journal volume & issue
Vol. 14, no. 6
p. 539

Abstract

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Mn5Ge3 is a ferromagnetic phase of the Mn-Ge system that is a potential contact material for efficient spin injection and detection. Here, we investigate the creation of Mn5Ge3-based contacts on a Ge/SiGe quantum well heterostructure via solid-state synthesis. X-ray diffraction spectra fitting indicates the formation of Mn5Ge3-based contacts on bulk Ge and Ge/SiGe. High-resolution scanning transmission electron microscopy imaging and energy dispersive X-ray spectroscopy verify the correct Mn5Ge3-based phase formation. Schottky diode measurements, transmission line measurements, and Hall measurements reveal that Mn5Ge3-based contacts serve as good p-type contacts for Ge/SiGe quantum well heterostructures due to having a low Schottky barrier height of 0.10eV (extracted from a Mn5Ge3/n-Ge analogue) and a contact resistance in the order of 1 kΩ. Furthermore, we show that these electrical characteristics have a gate-voltage dependence, thereby providing tunability.

Keywords