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The development of wireless communications is driving the need for compact radiofrequency (RF) devices with up to terahertz (THz) frequency and fabrication processes compatible with that of complementary-metal-oxide-semiconductor (CMOS) transistors. Aligned carbon nanotube (A-CNT) film is a promising candidate semiconductor that can be used to build both CMOS field-effect transistors (FETs) for digital integrated circuits (ICs) and radiofrequency (RF) transistors with frequencies beyond 1 THz for analogue ICs. Herein, we demonstrate the first MOS FET with a cut-off frequency beyond 1 THz on a high-quality A-CNT array film, and with a carrier mobility of 2,000 cm2 V− 1 s− 1 and better scaling characteristics than all semiconductors, including GaAs and InP. The fabricated CNT MOS FETs present a record performance that includes an on-state current of 3.02 mA µm− 1, a peak transconductance of 2.17 mS µm− 1 at a bias of − 1 V, and a saturation velocity of 3.5 × 107 cm s− 1. Through optimising device structure and fabrication process, in particular the introduction of a Y-gate, a 35 nm-gate length A-CNT MOS FET is fabricated that shows extrinsic current-gain/power-gain and cut-off frequencies of up to 551 GHz/1024 GHz, representing the fastest MOS FET for RF applications. Furthermore, CNT-based mmWave band (30 GHz) RF amplifiers are demonstrated with a high gain of 21.4 dB.

The graphite-based materials with a delocalized π electron system exhibited fast charge transfer with physically adsorbed iodide ions, thus revealing desirable IOR catalytic activity.

Intrinsic antiferromagnetism in van der Waals (vdW) monolayer (ML) crystals enriches our understanding of two-dimensional (2D) magnetic orders and presents several advantages over ferromagnetism in spintronic applications. However, studies of 2D intrinsic antiferromagnetism are sparse, owing to the lack of net magnetisation. Here, by combining spin-polarised scanning tunnelling microscopy and first-principles calculations, we investigate the magnetism of vdW ML CrTe2, which has been successfully grown through molecular-beam epitaxy. We observe a stable antiferromagnetic (AFM) order at the atomic scale in the ML crystal, whose bulk is ferromagnetic, and correlate its imaged zigzag spin texture with the atomic lattice structure. The AFM order exhibits an intriguing noncollinear spin reorientation under magnetic fields, consistent with its calculated moderate magnetic anisotropy. The findings of this study demonstrate the intricacy of 2D vdW magnetic materials and pave the way for their in-depth analysis.

Treatment of depression with antidepressants is partly effective. Transcranial alternating current stimulation can provide a non-pharmacological alternative for adult patients with major depressive disorder. However, no study has used the stimulation to treat first-episode and drug-naïve patients with major depressive disorder. We used a randomized, double-blind, sham-controlled design to examine the clinical efficacy and safety of the stimulation in treating first-episode drug-naïve patients in a Chinese Han population. From 4 June 2018 to 30 December 2019, 100 patients were recruited and randomly assigned to receive 20 daily 40-min, 77.5 Hz, 15 mA, one forehead and two mastoid sessions of active or sham stimulation (n = 50 for each group) in four consecutive weeks (Week 4), and were followed for additional 4-week efficacy/safety assessment without stimulation (Week 8). The primary outcome was a remission rate defined as the 17-item Hamilton Depression Rating Scale (HDRS-17) score ≤ 7 at Week 8. Secondary analyses were response rates (defined as a reduction of ≥ 50% in the HDRS-17), changes in depressive symptoms and severity from baseline to Week 4 and Week 8, and rates of adverse events. Data were analysed in an intention-to-treat sample. Forty-nine in the active and 46 in the sham completed the study. Twenty-seven of 50 (54%) in the active treatment group and 9 of 50 (18%) in the sham group achieved remission at the end of Week 8. The remission rate was significantly higher in the active group compared to that in the sham group with a risk ratio of 1.78 (95% confidence interval, 1.29, 2.47). Compared with the sham, the active group had a significantly higher remission rate at Week 4, response rates at Weeks 4 and 8, and a larger reduction in depressive symptoms from baseline to Weeks 4 and 8. Adverse events were similar between the groups. In conclusion, the stimulation on the frontal cortex and two mastoids significantly improved symptoms in first-episode drug-naïve patients with major depressive disorder and may be considered as a non-pharmacological intervention for them in an outpatient setting.

The van der Waals (vdW) strategy is promising for overcoming the Fermi pinning challenge in two-dimensional (2D) transistors. However, the lack of advanced-node lithography-compatible methods hinders wafer-scale integrated manufacturing of vdW contacts. We report a yttrium-doping-induced phase-transition technology for converting semiconducting trigonal prismatic (2H) into heavily doped metallic octahedral (1T) MoS2 to achieve suitable vdW band alignment and ideal ohmic contacts. This Y-doped 1T-MoS2 is a vdW metallic buffer, and it improves carrier transfer efficiency from the metal electrode to 2H MoS2. We developed a solid-state-source three-step doping method (plasma-deposition-annealing) and achieved Å-thickness surface doping with yttrium atoms replacing sulfur atoms in the top surface of MoS2, thus forming self-aligned Y-doped 1T-MoS2 vdW ohmic contacts lithographically patterned in the source and drain regions. We fabricated 10-nm MoS2 FETs with Y-doped 1T-MoS2 vdW contacts in 2-inch wafers exhibiting nearly ideal ohmic contact with an ignorable Schottky barrier, achieved the smallest contact-resistance Rc in all 2D TMD FETs (less than 117-ohm micrometers) and a total-resistance (235-ohm micrometers) more than three times smaller than those of the best-reported 2D n-type FETs (greater than 800-ohm micrometers), showing high performance with an excellent on-current density of 1.22 milliamperes per micrometer at a small drain voltage of 0.7 V, a high ballistic ratio of 80%, and a record transconductance of 3.2 millisiemens per micrometer.

Carbon nanotube (CNT) field-effect transistors (FETs) and integrated circuits (ICs) have been predicted and demonstrated to be some of the most promising candidates for radiation-hardened electronics. The studies mainly focused on the radiation response of the whole transistors, and experiments or analyses to reveal the detailed radiation responses of different components of the FET were absent. Here, we use a controllable experimental method to decouple the total ionizing dose (TID) radiation effects on different individual components of top-gate CNT FETs, including the CNT channel, gate dielectric, and substrate. The substrate is found to be more vulnerable to radiation damage than the gate dielectric and CNT film in FETs. Furthermore, the CNT film not only acts as a radiation-hardened semiconducting channel but also protects the channel/substrate interface by partially shielding the substrate from radiation damage. On the basis of the experimental data, a model is built to predict the irradiation resistance limit of CNT top-gated FETs, which can withstand at least 155 kGy irradiation.

Transistors on aligned semiconducting carbon nanotubes (A-CNTs) have been considered a promising substitute for mainstream Si transistors to extend integrated circuit (IC) technology owing to their potential advantages of easy miniaturization and high energy efficiency, but whether A-CNT FETs can be scalably fabricated with ultrascaled whole dimensions while maintaining high performance remains questionable. Here, we explore the whole size scaling down potential of A-CNT transistors and demonstrate the possibility of implementing such small-geometry transistors in ultra-large-scale ICs that consist of billions of transistors. A-CNT transistors with a contacted gate pitch (CGP) of 175 nm have been achieved by simultaneously scaling the gate length and the contact length, and exhibit an on-current of 2.24 mA/μm and a peak transconductance of 1.64 mS/μm, surpassing silicon 45 nm node transistors in terms of both size and electronic performance. A static random-access memory (SRAM) cell has been built using six A-CNT transistors in an area of 0.967 μm2, which is comparable to the commercial silicon 90 nm technology node and is the smallest SRAM cell based on non-Si semiconductors. Furthermore, a full-contact structure is introduced between the metal and A-CNTs to achieve a contact resistance as low as 90 Ω·μm and to reduce the dependence on the contact length. A-CNT transistors downsized to a CGP of 55 nm (corresponding to the silicon 10 nm technology node) have been demonstrated to outperform 10 nm Si MOS transistors in terms of carrier mobility and Fermi velocity, indicating the tremendous potential of A-CNT transistors in high-performance digital ICs of sub 10 nm nodes.

Colletotrichum fungi infect a wide diversity of monocot and eudicot hosts, causing plant diseases on almost all economically important crops worldwide. In addition to its economic impact, Colletotrichum is a suitable model for the study of gene family evolution on a fine scale to uncover events in the genome that are associated with the evolution of biological characters important for host interactions. Here we present the genome sequences of 30 Colletotrichum species, 18 of them newly sequenced, covering the taxonomic diversity within the genus. A time-calibrated tree revealed that the Colletotrichum ancestor diverged in the late Cretaceous around 70 million years ago (mya) in parallel with the diversification of flowering plants. We provide evidence of independent host jumps from eudicots to monocots during the evolution of this pathogen, coinciding with a progressive shrinking of the degradative arsenal and expansions in lineage specific genes. Comparative transcriptomics of four reference species with different evolutionary histories and adapted to different hosts revealed similarity in gene content but differences in the modulation of their transcription profiles. Only a few orthologs show similar expression profiles on different plant cell walls. Combining genome sequences and expression profiles we identified a set of core genes, such as specific transcription factors, involved in plant cell wall degradation in Colletotrichum.Together, these results indicate that the ancestral Colletotrichum were associated with eudicot plants and certain branches progressively adapted to different monocot hosts, reshaping part of the degradative and transcriptional arsenal.

Brain-inspired neuromorphic computing is expected for breaking through the bottleneck of the computer of conventional von Neumann architecture. To this end, the first step is to mimic functions of biological neurons and synapses by electronic devices. In this paper, synaptic transistors were fabricated by using carbon nanotube (CNT) thin films and interface charge trapping effects were confirmed to dominate the weight update of the synaptic transistors. Large synaptic weight update was realized due to the high sensitivity of the CNTs to the trapped charges in vicinity. Basic synaptic functions including inhibitory post-synaptic current (IPSC), excitatory post-synaptic current (EPSC), spike-timing-dependent plasticity (STDP), and paired-pulse facilitation (PPF) were mimicked. Large dynamic range of STDP (> 2,180) and low power consumption per spike (∼ 0.7 pJ) were achieved. By taking advantage of the long retention time of the trapped charges and uniform device-to-device performance, long-term image memory behavior of neural network was successfully imitated in a CNT synaptic transistor array.