Ferroelectric switching of spin-to-charge conversion can be achieved at room temperature in germanium telluride — a Rashba ferroelectric semiconductor — deposited on a silicon substrate.

The development of spintronic devices has been limited by the poor compatibility between semiconductors and ferromagnetic sources of spin. The broken inversion symmetry of some semiconductors may allow for spin–charge interconversion, but its control by electric fields is volatile. This has led to interest in ferroelectric Rashba semiconductors, which combine semiconductivity, large spin–orbit coupling

Electrical modulation of nonlinear optical signals is crucial for emerging applications in communications and photonic circuits. However, current methods of modulating the second-order optical susceptibility involve indirectly and inefficiently changing the third-order susceptibility. Here we show that electrical switching of the crystal structure of monolayer molybdenum ditelluride can be used to

Data-intensive computing operations, such as training neural networks, are essential for applications in artificial intelligence but are energy intensive. One solution is to develop specialized hardware onto which neural networks can be directly mapped, and arrays of memristive devices can, for example, be trained to enable parallel multiply–accumulate operations. Here we show that memcapacitive devices

Large-area electronics based on metal-oxide thin-film transistors can be used to create integrated phased arrays for radiofrequency front-ends in 5G — and future 6G — communication systems.

Large-aperture electromagnetic phased arrays can provide directionally controlled radiation signals for use in applications such as communications, imaging and power delivery. However, their deployment is challenging due to the lack of an electronic technology capable of spanning large physical dimensions. Furthermore, applications in areas such as aviation, the Internet of Things and healthcare require

From submillimetre-sized devices to entire rooms, wireless power transfer is a valuable technology in a range of settings.

The direction of photocurrent in a p–n heterojunction device can be switched by using different wavelengths of light.

Semiconductor p–n junctions provide rectification behaviour and act as building blocks in many electronic devices. However, the typical junction configuration restricts the potential functionalities of devices. Here we report a light-detection electrochemical cell that is based on vertically aligned p-AlGaN/n-GaN p–n heterojunction nanowires in an electrolyte environment. After decorating the nanowires

Flexible light-emitting devices that can transform from two-dimensional to three-dimensional (3D) forms could be of use in the development of next-generation displays. Various approaches for converting two-dimensional structures into 3D architectures have been explored, including origami methods that rely on folding along lines in which a structure has been thinned. But the fabrication of foldable

Reverse engineering the brain by mimicking the structure and function of neuronal networks on a silicon integrated circuit was the original goal of neuromorphic engineering, but remains a distant prospect. The focus of neuromorphic engineering has thus been relaxed from rigorous brain mimicry to designs inspired by qualitative features of the brain, including event-driven signalling and in-memory information

To realize the potential of artificial intelligence in medical imaging, improvements in imaging capabilities are required, as well as advances in computing power and algorithms. Hybrid inorganic–organic metal halide perovskites, such as methylammonium lead triiodide (MAPbI3), offer strong X-ray absorption, high carrier mobilities (µ) and long carrier lifetimes (τ), and they are promising materials

Doping is required to modulate the electrical properties of semiconductors but introduces impurities that lead to Coulomb scattering, which hampers charge transport. Such scattering is a particular issue in two-dimensional semiconductors because charged impurities are in close proximity to the atomically thin channel. Here we report the remote modulation doping of a two-dimensional transistor that

Long and thin graphene nanoribbons with atomically smooth edges can be fabricated in high yield by squashing carbon nanotubes.

Graphene nanoribbons are of potential use in the development of electronic and optoelectronic devices. However, the preparation of narrow and long nanoribbons with smooth edges, sizeable bandgaps and high mobilities is challenging. Here we show that sub-10-nm-wide semiconducting graphene nanoribbons with atomically smooth closed edges can be produced by squashing carbon nanotubes using a high-pressure

Magnetoquasistatic wireless power transfer can be used to charge and power electronic devices such as smartphones and small home appliances. However, existing coil-based transmitters, which are composed of wire conductors, have a limited range. Here we show that multimode quasistatic cavity resonance can provide room-scale wireless power transfer. The approach uses multidirectional, widely distributed

Flexible devices based on organic semiconductors could be of use in the development of wearable electronics and the Internet of Things, but face competition from other established and emerging technologies.

The continuing development of consumer electronics, mobile communications and advanced computing technologies has led to a rapid growth in data traffic, creating challenges for the communications industry. Light-emitting diode (LED)-based communication links are of potential use in both free space and optical interconnect applications, and LEDs based on emerging semiconductor materials, which can offer

Multichannel electrophysiological sensors and stimulators—particularly those used to study the nervous system—are usually based on monolithic microelectrode arrays. However, the architecture of such arrays limits flexibility in electrode placement and scaling to a large number of nodes, especially across non-contiguous locations. Here we report wirelessly networked and powered electronic microchips

The development of electronics is increasingly dependent on low-cost, flexible, solution-processed semiconductors. Colloidal quantum dots are solution-processed semiconducting nanocrystals that have a size-tunable bandgap and can be fabricated on a range of substrates. Here we review developments in colloidal quantum dot electronics, focusing on luminescent, optoelectronic, memory and thermoelectric

Microthermoelectric modules can be used as energy harvesters, active coolers and thermal sensors in integrated systems. However, manufacturing such modules with traditional microfabrication processes is costly and produces only two-dimensional thermoelectric films, which limit the formation of high-temperature gradients and thus the amount of power generated. Here we show that microscale three-dimensional

Vertical organic thin-film transistors can be used to create complementary circuits that operate at high frequencies.

A flexible microprocessor with more than 18,000 NAND gates can be manufactured using metal-oxide thin-film transistor technology.

In infectious disease diagnosis, results need to be communicated rapidly to healthcare professionals once testing has been completed so that care pathways can be implemented. This represents a particular challenge when testing in remote, low-resource rural communities, in which such diseases often create the largest burden. Here, we report a smartphone-based end-to-end platform for multiplexed DNA

Technology breakthroughs at the 2021 Symposia on VLSI Technology and Circuits.

An electronic network of compact oscillatory circuits can be used to find the optimal ground state of Ising Hamiltonians.

Combinatorial optimization problems belong to the non-deterministic polynomial time (NP)-hard complexity class, and their computational requirements scale exponentially with problem size. They can be mapped into the problem of finding the ground state of an Ising model, which describes a physical system with converging dynamics. Various platforms, including optical, electronic and quantum approaches

An organic phototransistor with two complementary bulk heterojunctions exhibits light-intensity-dependent adaptation behaviour that mimics the behaviour of the human visual system.

Wireless on-demand drug delivery systems exploit exogenous stimuli—acoustic waves, electric fields, magnetic fields and electromagnetic radiation—to trigger drug carriers. The approach allows drugs to be delivered with controlled release profiles and minimal off-target effects. Recent advances in electronics and materials engineering have led to the development of sophisticated systems designed for

The development of artificial visual systems that mimic biological systems requires devices that can autonomously adapt their response to varying stimuli. However, emulating biological feedforward visual adaptation is challenging and requires complementary photoexcitation and inhibition, ideally in a single device. Here we show that an organic transistor that incorporates two bulk heterojunctions is

Owing to its energy efficiency, silicon complementary metal–oxide–semiconductor (CMOS) technology is the current driving force of the integrated circuit industry. Silicon’s narrow bandgap has led to the advancement of wide-bandgap semiconductor materials, such as gallium nitride (GaN), being favoured in power electronics, radiofrequency power amplifiers and harsh environment applications. However,

The human body can be used as a medium to couple ambient energy and transmit power to wearable devices.

Lateral-channel dual-gate organic thin-film transistors have been used in pseudo complementary metal–oxide–semiconductor (CMOS) inverters to control switching voltage. However, their relatively long channel lengths, combined with the low charge carrier mobility of organic semiconductors, typically leads to slow inverter operation. Vertical-channel dual-gate organic thin-film transistors are a promising

Carbon materials such as graphene are of potential use in the development of electronic devices because of properties such as high mechanical strength and electrical and thermal conductivity. However, technical challenges, including difficulties in generating and modulating bandgaps, have limited the application of such materials. Here we show that the bandgaps of bilayers of two-dimensional C3N can

Two-dimensional structures that are engineered to manipulate electromagnetic radiation are becoming increasingly practical and could be of use in bioelectronics and communications.

Magnetic tunnel junctions with a hybrid free layer design can be used to electrically read and write domain walls.

The manipulation of fast domain wall motion in magnetic nanostructures could form the basis of novel magnetic memory and logic devices. However, current approaches for reading and writing domain walls require external magnetic fields, or are based on conventional magnetic tunnel junctions (MTJs) that are not compatible with high-speed domain wall motion. Here we report domain wall devices based on

Strong electron–electron interactions between adjacent nanoscale wires can lead to one-dimensional Coulomb drag, where current in one wire induces a voltage in the second wire via Coulomb interactions. This effect creates challenges for the development of nanoelectronic devices. Quantum spin Hall (QSH) insulators are a promising platform for the development of low-power electronic devices due to their

Electrically tunable metadevices can add novel functionalities to electronic and electromagnetic systems such as antennas and cloaking technologies. However, current microwave metadevices are based on materials that require sophisticated and expensive fabrication processes, and are not compatible with large-area and high-throughput deposition techniques on flexible platforms. Here we report reconfigurable

The development of next-generation wireless communication technology requires integrated radiofrequency devices capable of operating at frequencies greater than 90 GHz. Carbon nanotube field-effect transistors are promising for such applications, but key performance metrics, including operating frequency, at present fall below theoretical predictions. Here we report radiofrequency transistors based

Electric fields drive the degradation of wide-bandgap semiconductor devices. However, directly mapping the electric field inside an active device region remains challenging. Here we show that electric-field-induced second harmonic generation can be used to map the electric field in the device channel of GaN-based high-electron-mobility transistors at submicrometre resolution. To illustrate the capabilities

Boron arsenide could be used as a high-thermal-conductivity cooling substrate in gallium nitride power devices.

Curvy imagers that can adjust their shape are of use in imaging applications that require low optical aberration and tunable focusing power. Existing curvy imagers are either flexible but not compatible with tunable focal surfaces, or stretchable but with low resolution and pixel fill factors. Here, we show that curvy and shape-adaptive imagers with high pixel fill factors can be created by transferring

Two-dimensional (2D) semiconducting transition metal dichalcogenides could be used to build high-performance flexible electronics. However, flexible field-effect transistors (FETs) based on such materials are typically fabricated with channel lengths on the micrometre scale, not benefitting from the short-channel advantages of 2D materials. Here, we report flexible nanoscale FETs based on 2D semiconductors;

Thermal management is critical in modern electronic systems. Efforts to improve heat dissipation have led to the exploration of novel semiconductor materials with high thermal conductivity, including boron arsenide (BAs) and boron phosphide (BP). However, the integration of such materials into devices and the measurement of their interface energy transport remain unexplored. Here, we show that BAs

Bioelectronic systems typically rely on radiofrequency wireless components to interface with the human body, but such components are bulky and energy-demanding, which limits the performance of the systems. Metasurfaces—artificial two-dimensional materials with subwavelength structure—can be engineered to control electromagnetic fields around the human body and could be used to overcome the current

Wireless power transmission and energy harvesting techniques could be used to power and operate devices in, on and around the human body. However, near-field power transmission approaches are limited by distance, and the efficiency of far-field radiofrequency methods is limited by the body shadowing effect. Here, we show that the body-coupling characteristics of electromagnetic waves—which are either

Future devices for the Internet of Things will require communication systems that can deliver higher data rates at low power. Backscatter radio—in which wireless communication is achieved via reflection rather than radiation—is a low-complexity approach that requires a minimal number of active elements. However, it is typically limited to data rates of hundreds of megabits per second because of the

A single biological neuron can efficiently perform Boolean operations. Artificial neuromorphic systems, on the other hand, typically require several devices to complete a single operation. Here, we show that neuristors that exploit the intrinsic polarity of two-dimensional materials can perform logic operations in a single device. XNOR gates can be made using ambipolar tungsten diselenide (WSe2), NOR

Humans detect tactile stimuli through a combination of pressure and vibration signals using different types of cutaneous receptor. The development of artificial tactile perception systems is of interest in the development of robotics and prosthetics, and artificial receptors, nerves and skin have been created. However, constructing systems with human-like capabilities remains challenging. Here, we

The coronavirus pandemic and an increased demand for semiconductor technology has led to a global chip shortage — and a re-evaluation of global supply chains.

Unipolar barrier structures are used to suppress dark current in photodetectors by blocking majority carriers. Designing unipolar barriers with conventional materials is challenging due to the strict requirements of lattice and band matching. Two-dimensional materials have self-passivated surfaces and tunable band structures, and can thus be used to design unipolar barriers in which lattice mismatch

Magnetoelectric systems could be used to develop magnetoelectric random access memory and microsensor devices. One promising system is the two-phase 3-1-type multiferroic nanocomposite in which a one-dimensional magnetic column is embedded in a three-dimensional ferroelectric matrix. However, it suffers from a number of limitations including unwanted leakage currents and the need for biasing with a

The implementation of memristive synapses in neuromorphic computing is hindered by the limited reproducibility and high energy consumption of the switching behaviour of the devices. Typical filament-type memristors suffer, in particular, from temporal and spatial variation in the set voltage and resistance states due to stochastic filament formation. Here, we report memristors based on two-dimensional

Unique circumstances in Taiwan led to the creation of the foundry model, where an integrated circuit manufacturer has no products of its own and its plants produce only customer designs. The model has reshaped the global semiconductor industry and is well positioned to be at the heart of technological innovation in the industry.

Sub-1-nm vertical field-effect transistors can be created by transferring pre-made metal film contacts onto two-dimensional materials.

A superconducting electromechanical device at cryogenic temperatures can be probed using optical fibres and a commercial phase modulator.

A major challenge to the scalability of cryogenic computing platforms is the heat load associated with the growing number of electrical cable connections between the superconducting circuitry and the room-temperature environment. Compared with electrical cables, optical fibres have significantly lower thermal conductivity and are widely used in modern telecommunications. However, optical modulation

Graphene has a range of properties that makes it suitable for building devices for the Internet of Things. However, the deployment of such devices will also likely require the development of suitable graphene-based hardware security primitives. Here we report a physically unclonable function (PUF) that exploits disorders in the carrier transport of graphene field-effect transistors. The Dirac voltage

With careful planning and a focus on developing expertise, government policy has helped Taiwan become a centre for semiconductor innovation.