A team of researchers from the College of Engineering at Seoul National University, led by Professor Gwan-Hyoung Lee, has made significant strides in the field of semiconductor technology with the development of a groundbreaking synthesis technique for 2D semiconductors. This innovative approach allows for the direct growth of wafer-scale single-crystal transition metal dichalcogenides (TMDs) on various substrates, paving the way for advanced semiconductor applications. Their findings, published in the esteemed journal Nature, highlight the increasing reliance on novel materials and methods amidst the surge of artificial intelligence (AI) technologies demanding superior semiconductor performance.
For decades, semiconductor research has focused on silicon-based materials, but as the needs of modern devices evolve, so too does the search for alternatives. TMDs, with their remarkable electrical properties and ultra-thin structures, are gaining traction as leading candidates to meet these new demands. However, industrially viable synthesis methods have lagged behind, leaving a critical gap in the mass production of high-quality 2D semiconductors. The conventional method of chemical vapor deposition (CVD) is widely adopted but suffers from issues like compromised electrical properties and the complexities involved in transferring TMDs onto other substrates.
As the semiconductor realm modernizes, the epitaxy technique—traditionally relied upon to grow TMDs on highly crystalline substrates—also presents its own set of challenges. These include the inherent limitations concerning substrate compatibility and the necessity of a transfer process that complicates production. Addressing these limitations is imperative for the semiconductor community, as they hinder the development of advanced 3D integration technologies that depend on the high quality of TMDs, which are critical for future electronic devices.
Embracing the challenge, the specialized research group crafted a transformative technique named “Hypotaxy.” This inventive synthesis method employs 2D materials such as graphene and hexagonal boron nitride as guiding templates. By utilizing these materials, the researchers can perfectly align TMD crystals, enabling the production of single-crystalline TMD films on any substrate without sacrificing performance. This development marks a first in the field, potentially revolutionizing the way 2D semiconductors are synthesized. The term “Hypotaxy” itself communicates the method’s essence; derived from the Greek words for “downward arrangement,” it aptly describes the downward growth characteristic of these synthesized films.
A standout feature of Hypotaxy is its capacity to operate at relatively low temperatures—around 400°C—making it seamless to integrate into the existing semiconductor manufacturing landscape. Moreover, the graphene templates used in the process naturally disappear during synthesis, eliminating the need for complex removal procedures. This results in improved efficiency and promises to enhance the quality of the final products. With Hypotaxy’s precision in controlling the thickness of the metal film, researchers can regulate the number of TMD layers, thereby optimizing device performance.
The implications of this technology extend far beyond the laboratory. Semiconductor devices constructed using TMDs synthesized through Hypotaxy exhibit remarkable charge carrier mobility and device uniformity, indicating that this technique carries the potential to spearhead innovations in high-performance electronic devices. As the demand for semiconductor integration increases, these findings underscore Hypotaxy’s role in addressing the evolving requirements laid out by burgeoning AI applications and other modern technological endeavors.
Although the initial focus of Hypotaxy has been on 2D semiconductors, its versatility means it holds promise for the synthesis of various crystalline thin-film materials. This versatility would allow researchers to explore avenues that were previously hindered by the limitations of traditional synthesis methods. As Hypotaxy offers unprecedented control over crystal orientation and structure through templating techniques, it has the potential to stimulate further innovations across numerous fields of materials engineering.
Professor Gwan-Hyoung Lee has been vocal about the potential impact of their discovery, expressing that Hypotaxy overcomes the historical limitations associated with the epitaxy method, a process that has dominated semiconductor growth since its inception in the 1930s. As semiconductor integration becomes essential for the advancements of next-generation AI systems, the research team’s expectations for Hypotaxy are high. They view it not merely as an incremental step in material science but as a revolutionary paradigm shift that may define the future landscape of semiconductor technology.
Reflecting on the challenging research journey, Donghoon Moon, the publication’s first author, spoke about the need to rethink established paradigms in materials synthesis. He emphasized how Hypotaxy emerged from an unconventional viewpoint of existing approaches, showcasing the significance of fresh perspectives in driving scientific inquiry and innovation. Looking ahead, Moon plans to continue researching previously perceived challenges, including synthesizing moiré structures that were previously deemed impossible to fabricate using conventional methods.
As this research gains traction, it positions Seoul National University and its College of Engineering as a pivotal contributor to the evolving narrative of semiconductor technology. The institution was founded in 1946 and has built an impressive legacy of fostering talent and innovation, serving as an essential force for both industrial advancement in South Korea and on the global stage.
This groundbreaking research not only advances technology but also emphasizes the critical intersection of academia and industry. The innovative developments that emerge from institutions like SNU have the promise to redefine manufacturing processes and encourage exploration into new materials and applications. With continued investigation into Hypotaxy, the potential for unlocking new dimensions of semiconductor technology remains vast.
As the research continues to unfold, it serves as a reminder of the boundless possibilities that arise from human ingenuity and collaboration. The advances in semiconductor science herald a new era not only for electronics but for all applications relying on advanced materials and novel fabrication techniques—as researchers persist in reshaping the foundations of technology.
As the world progresses, the narrative of semiconductor development continues to evolve, driven by innovations such as Hypotaxy. This journey reflects not only the pursuit of knowledge but also the relentless ambition to enhance and expand human capabilities through technology.
Subject of Research: New synthesis technology of 2D semiconductors
Article Title: Hypotaxy of wafer-scale single-crystal transition metal dichalcogenides
News Publication Date: February 20, 2025
Web References: http://dx.doi.org/10.1038/s41586-024-08492-9
References: Nature Journal
Image Credits: © Nature, originally published in Nature
Keywords
semiconductor technology, 2D materials, transition metal dichalcogenides, synthesis methods, Hypotaxy, graphene, high-performance devices, semiconductor manufacturing, innovations, materials science.
