The evolution of silicon-centered semiconductor technology has continued for more than 50 years. In recent years, however, the physical limits of nanoscale miniaturization have begun to come into view, and research and development into “the next semiconductor” is advancing worldwide.

 

The key themes driving this research are single-atom-thick materials, using electron spin instead of charge, and controlling quantum phenomena. This section introduces some of the leading new materials and cutting-edge technologies in this space.

Overview

Graphene is a sheet-like material just one atom thick, made of carbon atoms arranged in a hexagonal lattice. It was first successfully isolated in 2004 at the University of Manchester, an achievement that earned the 2010 Nobel Prize in Physics.

Characteristics

・Electrical conductivity: roughly 100 times that of copper

・Electron mobility: more than 100 times that of silicon

・Mechanical strength: roughly 200 times that of steel

・High flexibility and transparency, with a light transmittance of 97%

Applications

・Ultra-high-speed transistors

・Flexible displays

・High-sensitivity sensors

・Electrode material for lithium-ion batteries

・Quantum devices and spintronics

Challenges

・Its band gap is zero, making ON/OFF control difficult in semiconductor applications.

・Mass, uniform production remains difficult, with CVD and transfer techniques serving as key enabling technologies.

Graphene is often described as a dream material, combining conductivity, flexibility, and strength.

Overview

Following graphene’s discovery, a broader family of materials just one to a few atomic layers thick has drawn significant attention. Representative examples include:

・MoS₂ (molybdenum disulfide)

・WS₂ (tungsten disulfide)

・h-BN (hexagonal boron nitride)

Characteristics

・Layers are held together by weak van der Waals forces.

・Extremely thin, flexible, and offering high carrier mobility.

・Unlike graphene, these materials possess a band gap — a key difference.

Applications

・Transistors (2D-FETs)

・Flexible electronic circuits

・Optical sensors and photodetectors

・Quantum devices and neuromorphic components

These materials are considered strong post-silicon candidates thanks to their combination of thinness, flexibility, and quantum effects.

Overview

Conventional semiconductors process information using the movement of electrons — that is, electric charge. Spintronics also makes use of electron spin, the electron’s magnetic orientation.

Characteristics

・Spin refers to an electron’s “up” or “down” magnetic state.

・Information can be retained without a continuous current flow, reducing power consumption.

・Practical applications, such as magnetic memory (MRAM), are already advancing.

Representative technologies

・Magnetic tunnel junctions (MTJ)

・Spin injection and detection techniques

・Spin-orbit torque (SOT) memory

Applications

・MRAM (non-volatile memory)

・Quantum computing

・AI accelerators (low-power computation)

Spintronics points toward semiconductors that can store information without continuously consuming electricity — a future memory technology.

Overview

Quantum dots are extremely small semiconductor particles, just a few nanometers in size. Due to quantum confinement effects, the wavelength of light they emit changes depending on their size.

Characteristics

・High brightness and high color purity in emitted light

・Excellent wavelength tunability

・Can reproduce the full RGB color range through fine control of particle size

Applications

・Quantum dot displays (QD-OLED)

・High color-rendering lighting

・Quantum computers and sensors

Quantum dots can be thought of as quantum particles that manipulate light — an extension of photonic semiconductor technology.

Overview

Carbon nanotubes are essentially graphene rolled into a tube shape, typically 1–2nm in diameter and ranging from a few micrometers to millimeters in length.

Characteristics

・Extremely high electrical and thermal conductivity

・Lightweight and highly strong, making them well suited to flexible substrates

Applications

・Transistors, transparent electrodes, batteries, and composite materials

・Companies such as Intel and IBM are already conducting research into CNT-based transistors

As a derivative of graphene, CNTs have broad potential applications in wiring, structural materials, and electronic devices.

Overview

Topological insulators are unusual materials that behave as an insulator internally while conducting electricity along their surface. Because electrons at the surface flow without scattering, they enable extremely low-loss conduction.

Characteristics

・Spin and charge are coupled together, producing spin-polarized currents.

・These materials are also relevant to fundamental research in quantum computing.

Applications

・Ultra-high-efficiency wiring materials

・Quantum information devices

・Technologies that merge with spintronics

Topological insulators offer the potential for wiring with resistance approaching zero.

Overview

Materials informatics uses AI to search through vast amounts of materials data to identify optimal combinations and processes. By combining experimentation with simulation, it can accelerate the discovery of new materials by orders of magnitude.

Example applications

・Optimizing thermal conductivity and electrical properties

・Automatically optimizing interfaces, defects, and structures

・Automated exploration for new semiconductor and battery materials

This emerging field is sometimes described as “a search engine for materials development.”

・Mass production of graphene and 2D materials, along with techniques to control their band gaps

・Practical implementation combining spintronics with quantum computing

・Autonomous, AI-driven materials design systems

・Energy harvesting using nanostructures, enabling self-powered electronics

・Expansion of environmentally friendly semiconductor materials focused on recycling and reduced resource use

Semiconductor technology is entering an era in which the focus shifts from simply controlling electrons to actively designing material properties themselves.

・Graphene, MoS₂, spintronics, quantum dots, and similar technologies represent efforts to move beyond the limits of silicon.

・Their shared goals are speed, low power consumption, new functionality, and environmental compatibility.

・The development of next-generation materials is closely tied to advances in AI, quantum technology, and renewable energy.

・The semiconductors of the future may no longer even take the form of a traditional chip.

1.Why is graphene difficult to use as a “semiconductor” in the traditional sense?

2.Why does spintronics offer low power consumption?

3.Among representative 2D materials, which one possesses a band gap?

 

Column Supervisor: Koji Kakumoto (Otis Group Co., Ltd.)

After studying abroad and working in planning and development at a trading company, he joined Otis Group Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as Representative Director, working to drive business growth and strengthen the organization.

 

This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.