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1. Improvements in 2D p-type WSe2 transistors towards ultimate CMOS scaling

   https://doi.org/10.1038/s41598-023-30317-4  

   Patoary, Naim Hossain; Xie, Jing; Zhou, Guantong; Al Mamun, Fahad; Sayyad, Mohammed; Tongay, Sefaattin; Esqueda, Ivan Sanchez (February 2023, Scientific Reports)

   Abstract This paper provides comprehensive experimental analysis relating to improvements in the two-dimensional (2D) p-type metal–oxide–semiconductor (PMOS) field effect transistors (FETs) by pure van der Waals (vdW) contacts on few-layer tungsten diselenide (WSe₂) with high-k metal gate (HKMG) stacks. Our analysis shows that standard metallization techniques (e.g., e-beam evaporation at moderate pressure ~ 10^–5 torr) results in significant Fermi-level pinning, but Schottky barrier heights (SBH) remain small (< 100 meV) when using high work function metals (e.g., Pt or Pd). Temperature-dependent analysis uncovers a more dominant contribution to contact resistance from the channel access region and confirms significant improvement through less damaging metallization techniques (i.e., reduced scattering) combined with strongly scaled HKMG stacks (enhanced carrier density). A clean contact/channel interface is achieved through high-vacuum evaporation and temperature-controlled stepped deposition providing large improvements in contact resistance. Our study reports low contact resistance of 5.7 kΩ-µm, with on-state currents of ~ 97 µA/µm and subthreshold swing of ~ 140 mV/dec in FETs with channel lengths of 400 nm. Furthermore, theoretical analysis using a Landauer transport ballistic model for WSe₂SB-FETs elucidates the prospects of nanoscale 2D PMOS FETs indicating high-performance (excellent on-state current vs subthreshold swing benchmarks) towards the ultimate CMOS scaling limit. 

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2. Corner- and edge-mode enhancement of near-field radiative heat transfer

   https://doi.org/10.1038/s41586-024-07279-2  

   Tang, Lei; Corrêa, Lívia M; Francoeur, Mathieu; Dames, Chris (May 2024, Nature)

   It is well established that near-field radiative heat transfer (NFRHT) can exceed Planck’s blackbody limit1 by orders of magnitude owing to the tunneling of evanescent electromagnetic frustrated and surface modes2-4, as has been demonstrated experimentally for NFRHT between two large parallel surfaces5-7 and between two subwavelength membranes8,9. However, while nanostructures can also sustain a much richer variety of localized electromagnetic modes at their corners and edges,10,11 the contributions of such additional modes to further enhancing NFRHT remain unexplored. Here, we demonstrate both theoretically and experimentally a new physical mechanism of NFRHT mediated by these corner and edge modes, and show it can dominate the NFRHT in the “dual nanoscale regime” in which both the thickness of the emitter and receiver, and their gap spacing, are much smaller than the thermal photon wavelengths. For two coplanar 20 nm thick SiC membranes separated by a 100 nm vacuum gap, the NFRHT coefficient at room temperature is both predicted and measured to be 830 W/m2K, which is 5.5 times larger than that for two infinite SiC surfaces separated by the same gap, and 1400 times larger than the corresponding blackbody limit accounting for the geometric view factor between two coplanar membranes. This enhancement is dominated by the electromagnetic corner and edge modes which account for 81% of the NFRHT between the SiC membranes. These findings are important for future NFRHT applications in thermal management and energy conversion. 

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3. Unlocking the Potential of 1D M2X3Y8 Ternary Transition Metal Chalcogenides: A Review

   https://doi.org/10.1021/acs.nanolett.5c00009  

   Antipina, Liubov Y; Wei, Jiang; Sorokin, Pavel B (May 2025, Nano Letters)

   AbstractClick to copy section link One-dimensional (1D) ternary transition metal chalcogenides (M2X3Y8) have emerged as a promising class of materials for advanced electronic and optoelectronic applications. This Mini-Review comprehensively explores recent advancements in their synthesis, characterization, and integration into functional devices. The studied nanowires display exceptional performance as semiconductor 1D nanostructures in photodetection, field-effect transistors, and gas sensing. Their unique 1D structure, tunable electronic properties, and high stability make them attractive candidates for future research and development in the field of materials science. 

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4. Vertical Organic Tunnel Field-Effect Transistors

   Liu, Shiyi; Tietze, Max; Al-Shadeedi, Akram; Kaphle, Vikash; Keum, Changmin; Lussem, Bjorn (July 2019, ACS applied electronic materials)

   Doping organic semiconductors has become a key technology to increase the performance of organic light-emitting diodes, solar cells, or field-effect transistors (OFETs). However, doping can be used not only to optimize these devices but also to enable new design principles as well. Here, a novel type of OFET is reported—the vertical organic tunnel field-effect transistor. Based on heterogeneously doped drain and source contacts, charge carriers are injected from an n-doped source electrode into the channel by Zener tunneling and are transported toward a p-doped drain electrode. The working mechanism of these transistors is discussed with the help of a tunnel model that takes energetic broadening of transport states in organic semiconductors and roughness of organic layers into account. The proposed device principle opens new ways to optimize OFETs. It is shown that the Zener junction included between the source and drain of the vertical organic tunnel field-effect transistors suppresses short channel effects and improves the saturation of vertical OFETs. 

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5. Fabrication of single color centers in sub-50 nm nanodiamonds using ion implantation

   https://doi.org/10.1515/nanoph-2022-0678  

   Xu, Xiaohui; Martin, Zachariah O.; Titze, Michael; Wang, Yongqiang; Sychev, Demid; Henshaw, Jacob; Lagutchev, Alexei S.; Htoon, Han; Bielejec, Edward S.; Bogdanov, Simeon I.; et al (January 2023, Nanophotonics)

   Abstract Diamond color centers have been widely studied in the field of quantum optics. The negatively charged silicon vacancy (SiV − ) center exhibits a narrow emission linewidth at the wavelength of 738 nm, a high Debye–Waller factor, and unique spin properties, making it a promising emitter for quantum information technologies, biological imaging, and sensing. In particular, nanodiamond (ND)-based SiV − centers can be heterogeneously integrated with plasmonic and photonic nanostructures and serve as in vivo biomarkers and intracellular thermometers. Out of all methods to produce NDs with SiV − centers, ion implantation offers the unique potential to create controllable numbers of color centers in preselected individual NDs. However, the formation of single color centers in NDs with this technique has not been realized. We report the creation of single SiV − centers featuring stable high-purity single-photon emission through Si implantation into NDs with an average size of ∼20 nm. We observe room temperature emission, with zero-phonon line wavelengths in the range of 730–800 nm and linewidths below 10 nm. Our results offer new opportunities for the controlled production of group-IV diamond color centers with applications in quantum photonics, sensing, and biomedicine. 

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