Wafer-scale and universal van der Waals metal semiconductor contact

Abstract

Van der Waals (vdW) metallic contacts have been demonstrated as a promising approach to reduce the contact resistance and minimize the Fermi level pinning at the interface of two-dimensional (2D) semiconductors. However, only a limited number of metals can be mechanically peeled and laminated to fabricate vdW contacts, and the required manual transfer process is not scalable. Here, we report a wafer-scale and universal vdW metal integration strategy readily applicable to a wide range of metals and semiconductors. By utilizing a thermally decomposable polymer as the buffer layer, different metals were directly deposited without damaging the underlying 2D semiconductor channels. The polymer buffer could be dry-removed through thermal annealing. With this technique, various metals could be vdW integrated as the contact of 2D transistors, including Ag, Al, Ti, Cr, Ni, Cu, Co, Au, Pd. Finally, we demonstrate that this vdW integration strategy can be extended to bulk semiconductors with reduced Fermi level pinning effect.

A Light‐Programmed Rewritable Lattice‐Mediated Multistate Memory for High‐Density Data Storage

“…Noted that the criteria considered here are different from those for the field-effect transistor used in the logic circuit, where the mobility and band gap are the main concerns. [30,31] Although ReS 2 is not known for possessing a high mobility, it is selected for two primary reasons. First, the formation energy required for creating sulfur vacancies in ReS 2 lattices can be achieved through visible light programming.…”

Tunable ohmic van der Waals-type contacts in monolayer C3N field-effect transistors

“…Considering the usability of the electrode in experiments and their lattice mismatch with ML C 3 N, bulk metals, including Pt, Pd, Au, and Ni, were chosen. [49][50][51][52] In addition, we considered 2D MXenes, including Zr 2 CF 2 , Ti 2 CF 2 , Zr 2 C(OH) 2 , and Ti 2 C(OH) 2 , because 2D MXenes can form van der Waals contacts with 2D semiconductors, which suppress Fermi level pinning and aid in achieving desired ohmic contacts. [53][54][55][56] To simulate the metal surface, ve layers of metal atoms were constructed for the bulk Au, Ni, Pd, and Pt electrodes, while the ML conguration was constructed for the layered 2D metals.…”

Hypoxia‐responsive AIEgens for precise disease theranostics

“…Wu and coworkers designed and synthesized an activatable dualmode fluorescence and photoacoustic (PA) probe, designated as NP-SPT-NO 2 , featuring an asymmetric star-shaped molecular architecture for imaging lymphatic metastasis in mice (Figure 4c) [76]. PA imaging presents the advantages of excellent penetration depth and spatial resolution, holding significant promise for clinical use [77][78][79][80][81][82]. In comparison with other organic PA probes, this probe developed in this work showcased a higher molar absorption coefficient, leading to intensified PA signals.…”