The development of competitive field-effect transistors based on two-dimensional semiconductors will also require the development of suitably scaled insulators.

Complementary metal–oxide–semiconductor (CMOS) logic circuits at their ultimate scaling limits place extreme demands on the properties of all materials involved. The requirements for semiconductors are well explored and could possibly be satisfied by a number of layered two-dimensional (2D) materials, such as transition metal dichalcogenides or black phosphorus. The requirements for gate insulators

Strain can be used to modify the band structure—and thus the electronic properties—of two-dimensional materials. However, research has focused on the use of monolayer graphene with a limited lowering of spatial symmetry and considered only the real-space pseudo-magnetic field. Here we show that lithographically patterned strain can be used to create a non-trivial band structure and exotic phase of

The electrical and mechanical robustness of thin metal film electrodes can be improved by adding an atomically thin interlayer, such as graphene, between the metal and the flexible substrate.

Magnetic field sensors are important in a variety of applications, including transport and medical devices. However, existing solid-state approaches for the detection of three-dimensional magnetic fields require multiple sensors, making the set-ups bulky. Here, we show that a single spin–orbit torque device composed of a Ta/CoFeB/MgO heterostructure can detect a vector magnetic field. In-plane and

Transistors are typically based on inorganic or organic semiconductors. Metals have generally been considered unsuitable for such use because bulk metals screen electric fields and thus achieving electrically tunable conductivity is difficult. Alternatively, gradients of counterions in films of metal nanoparticles functionalized with charged organic ligands can be used to construct electronic devices

Conformable electrodes can be used to manipulate the electrical properties of a Venus flytrap, creating actuators that can be wirelessly controlled.

Tunnel field-effect transistors (TFETs) rely on quantum-mechanical tunnelling and, unlike conventional metal–oxide–semiconductor field-effect transistors (MOSFETs), require less than 60 mV of gate voltage swing to induce one order of magnitude variation in the drain current at ambient temperature. III–V heterostructure TFETs are promising for low-power applications, but are outperformed by MOSFETs

Flexible electrodes that allow electrical conductance to be maintained during mechanical deformation are required for the development of wearable electronics. However, flexible electrodes based on metal thin films on elastomeric substrates can suffer from complete and unexpected electrical disconnection after the onset of mechanical fracture across the metal. Here we show that the strain-resilient

For our 2021 technology of the year, we explore the impact of the coronavirus pandemic on digital technology.

The increasingly prominent — and inescapable — role of digital technologies during the coronavirus pandemic has been accompanied by concerning trends in privacy and digital ethics. But more robust protection of our rights in the digital realm is possible in the future.

The coronavirus pandemic has forced students and educators across all levels of education to rapidly adapt to online learning. The impact of this — and the developments required to make it work — could permanently change how education is delivered.

The COVID-19 pandemic has brought an infodemic of misleading and unreliable information. In response, social media platforms have taken unprecedented steps to moderate content and promote official sources of information, which, combined with new policies and appropriate communication, could help tackle misinformation.

The potential of digital contact tracing to slow the spread of a virus had been quietly explored for over a decade before the COVID-19 pandemic thrust the technology into the spotlight. But can it actually be effective in the hard-to-model complexity of real-world social networks?

Wearable electronic devices, which allow physiological signals to be continuously monitored, can be used in the early detection of asymptomatic and pre-symptomatic cases of COVID-19.

Intrinsically stretchable electronics can form intimate interfaces with the human body, creating devices that could be used to monitor physiological signals without constraining movement. However, mechanical strain invariably leads to the degradation of the electronic properties of the devices. Here we show that strain-insensitive intrinsically stretchable transistor arrays can be created using an

Scaled-up quantum computers will require control interfaces capable of the manipulation and readout of large numbers of qubits, which usually operate at millikelvin temperatures. Advanced complementary metal–oxide–semiconductor (CMOS) technology is an attractive platform for delivering such interfaces. However, this approach is generally discounted due to its high power dissipation, which can lead

Owing to their adaptive interfacial properties, soft actuators can be used to perform more delicate tasks than their rigid counterparts. However, traditional polymeric soft actuators rely on energy conversion for actuation, resulting in high power input or slow responses. Here we report an electrical plant-based actuator that uses a conformable electrical interface as an electrical modulating unit

Resistive memory technologies could be used to create intelligent systems that learn locally at the edge. However, current approaches typically use learning algorithms that cannot be reconciled with the intrinsic non-idealities of resistive memory, particularly cycle-to-cycle variability. Here, we report a machine learning scheme that exploits memristor variability to implement Markov chain Monte Carlo

A flexible biosensing system with in-sensor machine-learning functionality can recognize up to 21 hand gestures in real time based on surface electromyography patterns from a forearm.

Hardware for deep neural network (DNN) inference often suffers from insufficient on-chip memory, thus requiring accesses to separate memory-only chips. Such off-chip memory accesses incur considerable costs in terms of energy and execution time. Fitting entire DNNs in on-chip memory is challenging due, in particular, to the physical size of the technology. Here, we report a DNN inference system—termed

Electronics with skin- or tissue-like mechanical properties, including low stiffness and high stretchability, can be used to create intelligent technologies for application in areas such as health monitoring and human–machine interactions. Stretchable transistors that provide signal-processing and computational functions will be central to the development of this technology. Here, we review the development

Wearable devices that monitor muscle activity based on surface electromyography could be of use in the development of hand gesture recognition applications. Such devices typically use machine-learning models, either locally or externally, for gesture classification. However, most devices with local processing cannot offer training and updating of the machine-learning model during use, resulting in

Technology breakthroughs at the 2020 IEEE International Electron Devices Meeting, which this year takes place online.

Two-dimensional semiconductors have a range of electronic and optical properties that can be used in the development of advanced electronic devices. However, unlike conventional silicon semiconductors, simple doping methods to monolithically assemble n- and p-type channels on a single two-dimensional semiconductor are lacking, which makes the fabrication of integrated circuitry challenging. Here we

Metasurfaces, which consist of arrays of subwavelength scatterers, can be used to precisely control incident electromagnetic fields, but are typically static once fabricated. A dynamically programmable array of terahertz meta-elements, in which each element can be individually reconfigured to allow controlled wavefront shaping, could be of value in terahertz applications such as wireless communication

The development of small, energy-efficient artificial intelligence edge devices is limited in conventional computing architectures by the need to transfer data between the processor and memory. Non-volatile compute-in-memory (nvCIM) architectures have the potential to overcome such issues, but the development of high-bit-precision configurations required for dot-product operations remains challenging

Isolated point defects in silicon that emit light at telecom wavelengths could help accelerate the development of quantum information technologies using commercial platforms.

Security is a critical aspect in modern circuit design, but research into hardware security at the device level is rare as it requires modification of existing technology nodes. With the increasing challenges facing the semiconductor industry, interest in out-of-the-box security solutions has grown, even if this implies introducing novel materials such as two-dimensional layered semiconductors. Here

A magnonic directional coupler based on yttrium iron garnet could be used to create integrated magnonic nanocircuits for logic operations.

Spin–orbit torque magnetization switching is an efficient method to control magnetization. In perpendicularly magnetized films, two types of spin–orbit torque are induced by driving a current: a damping-like torque and a field-like torque. The damping-like torque assists magnetization switching, but a large field-like torque pushes the magnetization towards the in-plane direction, resulting in a larger

Antiferromagnets are of potential use in the development of spintronic devices due to their ultrafast dynamics, insensitivity to external magnetic fields and absence of magnetic stray fields. Similar to their ferromagnetic counterparts, antiferromagnets can store information in the orientations of the collective magnetic order vector. However, the readout magnetoresistivity signals in simple antiferromagnetic

The electrical manipulation of magnetization and exchange bias in antiferromagnet/ferromagnet thin films could be of use in the development of the next generation of spintronic devices. Current-controlled magnetization switching can be driven by spin–orbit torques generated in an adjacent heavy-metal layer, but these structures are difficult to integrate with exchange bias switching and tunnelling

Given its potential for integration and scalability, silicon is likely to be a key platform for large-scale quantum technologies. Individual electron-encoded artificial atoms, formed by either impurities or quantum dots, have emerged as a promising solution for silicon-based integrated quantum circuits. However, single qubits featuring an optical interface, which is needed for long-distance exchange

Near-term applications of quantum information processors will rely on optimized circuit implementations to minimize the circuit depth, reducing the negative impact of gate errors in noisy intermediate-scale quantum (NISQ) computers. One approach to minimize the circuit depth is the use of a more expressive gate set. The XY two-qubit gate set can offer reductions in circuit depth for generic circuits

Could halide perovskites be of use in electronic devices beyond solar cells and LEDs?

The number of nodes typically used in sensory networks is growing rapidly, leading to large amounts of redundant data being exchanged between sensory terminals and computing units. To efficiently process such large amounts of data, and decrease power consumption, it is necessary to develop approaches to computing that operate close to or inside sensory networks, and that can reduce the redundant data

An ultrashort pulse of electric current can be used to switch the magnetization of a micrometre-scale magnetic element via spin–orbit torques.

An epicardial bioelectronic patch is an important device for investigating and treating heart diseases. The ideal device should possess cardiac-tissue-like mechanical softness and deformability, and be able to perform spatiotemporal mapping of cardiac conduction characteristics and other physical parameters. However, existing patches constructed from rigid materials with structurally engineered mechanical

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The development of approaches that can efficiently control the magnetization of magnetic materials is central to the creation of fast and low-power spintronic devices. Spin transfer torque can be used to electrically manipulate magnetic order in devices, but is typically limited to nanosecond timescales. Alternatively, spin–orbit torque can be employed, and switching with current pulses down to ~200 ps

The efficient generation, manipulation and detection of magnetic skyrmions are important for the development of future spintronic devices. One approach is to use electric-current-induced spin torques. Recently, thermally induced skyrmion motion has also been observed, but wider experimental evidence and its capabilities remain limited. Here we report the thermal generation, manipulation and thermoelectric

Ferroelectric field-effect transistors could play a key role in the development of data-centric computing hardware.

A cleaning–healing–cleaning method can effectively eliminate ionic defects at the surface of perovskite films, resulting in reliable and high-performance perovskite transistors.

Inexpensive radio-frequency devices that can meet the ultrahigh-frequency needs of fifth- and sixth-generation wireless telecommunication networks are required. However, combining high performance with cost-effective scalable manufacturing has proved challenging. Here, we report the fabrication of solution-processed zinc oxide Schottky diodes that can operate in microwave and millimetre-wave frequency

Light-emitting diodes based on halide perovskites have recently reached external quantum efficiencies of over 20%. However, the performance of visible perovskite light-emitting diodes has been hindered by non-radiative recombination losses and limited options for charge-transport materials that are compatible with perovskite deposition. Here, we report efficient, green electroluminescence from mixed-dimensional

Two-dimensional materials could play an important role in beyond-CMOS (complementary metal–oxide–semiconductor) electronics, and the development of memristors for information storage and neuromorphic computing using such materials is of particular interest. However, the creation of high-density electronic circuits for complex applications is limited due to low device yield and high device-to-device

Magnons, the quanta of spin waves, could be used to encode information in beyond-Moore computing applications, and magnonic device components, including logic gates, transistors and units for non-Boolean computing, have already been developed. Magnonic directional couplers, which can function as circuit building blocks, have also been explored, but have been impractical because of their millimetre

The discovery of ferroelectricity in oxides that are compatible with modern semiconductor manufacturing processes, such as hafnium oxide, has led to a re-emergence of the ferroelectric field-effect transistor in advanced microelectronics. A ferroelectric field-effect transistor combines a ferroelectric material with a semiconductor in a transistor structure. In doing so, it merges logic and memory

Organometal halide perovskite semiconductors could potentially be used to create field-effect transistors (FETs) with high carrier mobilities. However, the performance of these transistors is currently limited by the migration of ionic surface defects. Here, we show that a surface cleaning and passivation technique, which is based on a sequence of three solution-based steps, can reduce the concentration

Field-effect transistors that use carbon nanotubes as the channel material and an ion gel as the gate exhibit a high tolerance to radiation and can be recovered following radiation damage using a simple annealing process.

With the help of a gate electrode to control the charge state of individual molecules on graphene, information can be moved along a one-dimensional molecular chain, mimicking the behaviour of an electronic shift register.

Resistive switches, which are also known as memristors, are low-power, nanosecond-response devices that are used in a range of memory-centric technologies. Driven by an externally applied potential, the switching mechanism of valence change resistive memories involves the migration, accumulation and rearrangement of oxygen vacancies within a dielectric medium, leading to a change in electrical conductivity

The ability to tune the electronic properties of molecular arrays is an important step in the development of molecule-scale electronic devices. However, control over internal device charge distributions by tuning interactions between molecules has proved challenging. Here, we show that gate-tunable charge patterning can occur in one-dimensional molecular arrays on graphene field-effect transistors

Two-dimensional (2D) semiconductors are attractive for electronic devices with atomically thin channels. However, controlling the electronic properties of the 2D materials by incorporating impurity dopants is inherently difficult due to the limited physical space in the atomically thin lattices. Here we show that a solid-state ionic doping approach can be used to tailor the carrier type in 2D semiconductors

Atomically thin molybdenum disulfide (MoS2) is a promising semiconductor material for integrated flexible electronics due to its excellent mechanical, optical and electronic properties. However, the fabrication of large-scale MoS2-based flexible integrated circuits with high device density and performance remains a challenge. Here, we report the fabrication of transparent MoS2-based transistors and

Negative capacitance field-effect transistors have been proposed as a route to low-power electronics, but a lack of fundamental understanding limits progress.

The ability to estimate the uncertainty of predictions made by a neural network is essential when applying neural networks to tasks such as medical diagnosis and autonomous vehicles. The approach is of particular relevance when deploying the networks on devices with limited hardware resources, but existing competency-aware neural networks largely ignore any resource constraints. Here we examine the

Progress towards low-power electronics based on negative capacitance has been slow. For the field to develop, the gap between fundamental research on ferroelectric materials and the engineering of practical devices needs to be bridged.

A monocentric lens and a sensitive hemispherical imager can be combined to create a miniaturized camera that offers a field of view of 120°, deep depth of field and minimal optical aberration.