Chemical Synthesis and Integration of Highly Conductive PdTe₂ with Low‐Dimensional Semiconductors for p‐Type Transistors with Low Contact Barriers

Abstract

Low‐dimensional semiconductors provide promising ultrathin channels for constructing more‐than‐Moore devices. However, the prominent contact barriers at the semiconductor–metal electrodes interfaces greatly limit the performance of the obtained devices. Here, a chemical approach is developed for the construction of p‐type field‐effect transistors (FETs) with low contact barriers by achieving the simultaneous synthesis and integration of 2D PdTe2 with various low‐dimensional semiconductors. The 2D PdTe2 synthesized through a quasi‐liquid process exhibits high electrical conductivity (≈4.3 × 106 S m−1) and thermal conductivity (≈130 W m−1 K−1), superior to other transition metal dichalcogenides (TMDCs) and even higher than some metals. In addition, PdTe2 electrodes with desired geometry can be synthesized directly on 2D MoTe2 and other semiconductors to form high‐performance p‐type FETs without any further treatment. The chemically derived atomically ordered PdTe2–MoTe2 interface results in significantly reduced contact barrier (65 vs 240 meV) and thus increases the performance of the obtained devices. This work demonstrates the great potential of 2D PdTe2 as contact materials and also opens up a new avenue for the future device fabrication through the chemical construction and integration of 2D components.

Fermi Level Pinning Dependent 2D Semiconductor Devices: Challenges and Prospects

“…[119] More recently, a chemical method to directly synthesize metallic PdTe 2 on the surface of MoTe 2 has been demonstrated by tellurizing a predeposited Pd film at a low temperature. [120] A fine p-type vdW contact to MoTe 2 was achieved, showing a low SBH of 50 meV. Although it is not as good as a transferred vdW contact, the chemical approach is advantageous due to its simple process and great potential for large-scale integration.…”

Electrical and thermal transport properties of high crystalline PdTe2 nanoribbons under a strong magnetic field

“…The suspended PdTe 2 nanoribbons were fabricated on a silicon/silicon dioxide substrate through the eutectic tellurization of Pd thin films under Te vapor at a relatively low temperature of 300 °C. 16 From the scanning electron microscopy (SEM) image and X-ray diffraction (XRD) pattern in Fig. 1, it can be found that the present suspended PdTe 2 nanoribbons have a high crystallinity with a length of 8.89 μm, width of 1.3 μm, and thickness of 136.3 nm.…”

“…Furthermore, a strong magnetic field can reveal the carrier transport mechanism and explore its applicability under strong magnetic field conditions as well as some potential special applications. Based on the realization of the 2D high crystalline PdTe 2 synthesis technology, 16 we prepared suspended PdTe 2 nanoribbons integrated with the probing electrodes, which removed the substrate influence and eliminated the electrical and thermal contact resistances. The electrical resistivity and thermal conductivity were comprehensively measured by applying the direct current heating method at different temperatures up to 14 T, and the influencing mechanism of the magnetic field was studied in depth.…”

Morphotaxy of Layered van der Waals Materials

“…This 2D Cu 2 Se structure exhibited a band gap of 0.74 eV, again underscoring that phases distinct from naturally occurring materials can emerge using morphotaxial approaches. Finally, recent work by Zheng et al demonstrated the tellurization of thin Pd films by reacting with Te vapor at 300 °C . The resulting PdTe 2 showed higher conductivity (4.3 × 10 6 S m –1 ) compared to the starting Pd film (3.0 × 10 6 S m –1 ) and also resulted in reduced contact resistances for MoTe 2 and WSe 2 FETs …”