Strong Fermi-Level Pinning in GeS–Metal Nanocontacts
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-06-29 |
| Journal | The Journal of Physical Chemistry C |
| Authors | Yuxuan Sun, Zhen Jiao, Harold J. W. Zandvliet, Pantelis Bampoulis |
| Institutions | University of Twente |
| Citations | 5 |
Abstract
Section titled “Abstract”Germanium sulfide (GeS) is a layered monochalcogenide semiconductor with a band gap of about 1.6 eV. To verify the suitability of GeS for field-effect-based device applications, a detailed understanding of the electronic transport mechanisms of GeS-metal junctions is required. In this work, we have used conductive atomic force microscopy (c-AFM) to study charge carrier injection in metal-GeS nanocontacts. Using contact current-voltage spectroscopy, we identified three dominant charge carrier injection mechanisms: thermionic emission, direct tunneling, and Fowler-Nordheim tunneling. In the forward-bias regime, thermionic emission is the dominating current injection mechanism, whereas in the reverse-bias regime, the current injection mechanism is quantum mechanical tunneling. Using tips of different materials (platinum, n-type-doped silicon, and highly doped p-type diamond), we found that the Schottky barrier is almost independent of the work function of the metallic tip, which is indicative of a strong Fermi-level pinning. This strong Fermi-level pinning is caused by charged defects and impurities.