Unveiling China's Wafer-Scale 2D Semiconductor Revolution

Chinese researchers have achieved a monumental leap in semiconductor technology with the first successful fabrication of wafer-scale two-dimensional (2D) indium selenide (InSe) semiconductors, detailed in a landmark paper published in the prestigious journal Science. This breakthrough, led by Professor Liu Kaihui at Peking University's International Center for Quantum Materials in collaboration with Renmin University of China, addresses longstanding challenges in scaling 2D materials for practical electronics. Traditional silicon-based chips are approaching physical limits as defined by Moore's Law, prompting the global search for alternatives. 2D semiconductors like InSe, with their atomic-thin structure, promise superior electron mobility, lower power consumption, and enhanced performance in ultra-scaled devices.

Indium selenide (InSe), often dubbed a 'golden semiconductor' due to its optimal properties—including low effective mass, high thermal velocity, and a suitable bandgap—has long been eyed for next-generation integrated circuits. However, prior efforts yielded only microscopic flakes unsuitable for industrial production. The new solid-liquid-solid growth strategy changes this paradigm, enabling uniform, high-crystallinity films across entire 2-inch (approximately 5 cm) wafers. This scalability is crucial, mirroring the 12-inch silicon wafer standard in modern fabs, and paves the way for mass production of advanced chips in artificial intelligence, autonomous vehicles, and smart devices.

The Innovative Solid-Liquid-Solid Growth Technique

The core innovation lies in the novel 'solid-liquid-solid' (SLS) growth method, a meticulously engineered process that ensures precise stoichiometric control of indium (In) and selenium (Se) at a 1:1 ratio—critical for pure-phase InSe formation. Here's how it works step-by-step:

• First, an amorphous InSe thin film is deposited onto sapphire substrates using magnetron sputtering, providing a uniform starting layer.
• The wafer is then encapsulated with low-melting-point indium metal and sealed in a quartz cavity, creating an indium-rich localized environment.
• Upon heating to around 550°C, the indium liquifies, facilitating controlled dissolution of the amorphous film at the interface and subsequent recrystallization into single-phase, crystalline InSe.
• Cooling solidifies the structure, yielding wafers with unprecedented uniformity in thickness, phase purity, and crystallinity.

This technique overcomes vapor pressure disparities between In and Se that plagued vapor-phase methods, resulting in films rivaling exfoliated flakes in quality but at wafer scale. Peking University researchers optimized this for reproducibility, demonstrating its potential for industrial transfer.

Record-Breaking Performance Metrics

Transistor arrays fabricated from these InSe wafers set new benchmarks for 2D semiconductors. Key metrics include:

• Average electron mobility of 287 cm²/V·s at room temperature—far exceeding typical 2D films and approaching theoretical limits.
• Near-Boltzmann-limit subthreshold swing (SS) of 67 mV/decade, enabling sharp on-off switching with minimal voltage.
• Excellent short-channel behavior at sub-10 nm gate lengths: reduced drain-induced barrier lowering (DIBL), higher on/off ratios, and ballistic transport efficiency.
• Energy-delay product (EDP) and delay surpassing International Roadmap for Devices and Systems (IRDS) projections for silicon in 2037.

Compared to state-of-the-art Intel 3 nm nodes, InSe devices show superior parameters in ultrashort channels, hinting at a post-silicon future where 2D materials extend scaling beyond 1 nm.

China's Universities Leading the Charge

Peking University (PKU) and Renmin University exemplify China's rising dominance in materials science. Prof. Liu Kaihui's team, supported by the National Natural Science Foundation of China (grants 52025023, 52322205, 52250398), leveraged interdisciplinary expertise in quantum materials and device physics. This aligns with China's 'Made in China 2025' initiative, funneling resources into semiconductors amid global supply chain tensions.Discover academic opportunities in China. Such breakthroughs not only elevate university rankings but also attract global talent, fostering collaborations that drive innovation.

Related advances, like Fudan University's wafer-scale 2D molybdenum disulfide (MoS2) field-programmable gate array (FPGA) with ~4,000 transistors published in National Science Review, underscore a vibrant ecosystem.

Implications for Global Semiconductor Industry

Beyond academia, this positions China at the forefront of 2D electronics commercialization. Wafer-scale InSe could slash power use in data centers by 50% while boosting speed, critical for AI training models requiring exaflop computing. In consumer tech, expect thinner, cooler smartphones and wearables. Challenges remain in etching and metallization for 2D channels, but SLS scalability bridges lab-to-fab gaps.

For higher education, this spurs demand for specialized PhDs and postdocs in 2D materials. Institutions worldwide are ramping up programs; in China, PKU's quantum center exemplifies cutting-edge training.Explore research jobs in emerging fields like these.

Challenges Overcome and Remaining Hurdles

Past 2D efforts faltered on defects from non-uniform growth and phase impurities. SLS mitigates this via interface engineering. Future needs include larger wafers (8-12 inch), compatible dielectrics like HfO2, and 3D stacking. Environmental stability of InSe also requires passivation strategies.

• Scalability: From 2-inch to production-scale.
• Integration: Back-end-of-line compatibility with CMOS processes.
• Cost: Sputtering and encapsulation must compete with silicon fabs.

Stakeholder Perspectives and Expert Opinions

Science reviewers praised it as 'an advancement in crystal growth,' signaling peer validation. Industry analysts see InSe complementing silicon in hybrid chips. Chinese policymakers view it as strategic tech sovereignty. Western firms like TSMC eye licensing, though export controls loom.

Prof. Liu noted: 'This instills confidence for industrial demands.'

Future Outlook: Toward Commercialization

By 2030, expect pilot lines at labs like Songshan Lake Materials Lab. Projections: 2D chips capturing 20% logic market share. For academia, this fuels grants and startups. Students eyeing semiconductors should master CVD variants and device simulation.Career advice for academics.

Career Opportunities in 2D Semiconductor Research

This breakthrough amplifies demand for experts in China's booming sector. Roles span postdocs at PKU to faculty positions nationwide. Key skills: epitaxial growth, nano-fabrication, electrical characterization. Platforms like AcademicJobs connect talents to postdoc openings, professor jobs, and university jobs in semiconductors. Internships at national labs offer hands-on wafer processing experience.

Internationally, collaborations invite global researchers. Rate professors shaping this field via Rate My Professor.

Photo by Kelsey He on Unsplash

Conclusion: A New Era Dawns

China's wafer-scale 2D InSe semiconductors herald a transformative shift, blending university ingenuity with industrial promise. As silicon fades, 2D materials rise, powered by innovations from Peking and Renmin Universities. Stay ahead with higher ed jobs, career advice, and professor ratings at AcademicJobs.com. The future of electronics is atomically thin and brilliantly Chinese.