Mar 27, 2019
Professor Xiangfeng Duan
Professor Xiangfeng Duan is co-senior author of a forward looking Perspective article in a recent issue of the prestigious journal Nature
The article was also selected for Nature's 150 Year Anniversary Collection.
Titled “Van der Waals Integration Before and Beyond Two-dimensional Materials”, the article was published in the March 20, 2019 issue of the journal. 
A UCLA professor of chemistry and biochemistry, Duan is also an Associate Editor for the journal Nano Research.  In 2018, Duan was named one of the most influential scientific researchers by Clarivate Analytics.  
First author is Dr. Yuan Liu (left), a postdoctoral researcher co-supervised by Duan and co-senior author Professor Yu Huang (right) of the Department of Materials Science and Engineering at the UCLA Samueli School of Engineering. 
The heterogeneous integration of dissimilar materials is a long pursuit of material science community, and has defined the material foundation for modern electronics and enabled the information technology revolution over the past half century. The current material integration strategy such as chemical epitaxial growth usually involves strong chemical bonds and is typically limited to materials with strict structure match and processing compatibility. Materials with substantially different lattice structures cannot be epitaxially grown together without generating too much interfacial defects that seriously alter/degrade their intrinsic properties. 
In this Perspective article published in Nature, Duan and co-authors elaborate on an alternative material integration approach, van der Waals integration, in which heterogeneous materials are integrated together through weak van der Waals interactions. Over the past decade, the Duan group has pioneered this approach for creating a wide range of heterostructures and functional devices by assembling diverse 2D materials as well as 1D nanostructures and 3D bulk materials. This approach does does not rely on one-to-one chemical bonds or does not involve direct chemical processing on existing materials. It is thus not limited to materials that have similar lattice structures or require compatible synthetic conditions.
In the current article, the authors define the fundamental concepts and critical requirements for this emerging approach, review the historical background, and generalize it for flexible integration of distant materials with radically different chemical compositions, crystal structures or lattice orientations. They further prospect its potential for creating a new generation of heterostructures and superlattices with minimum interfacial defects or trapping states, which could help probe exotic electronic properties and/or realize novel device functions beyond the reach of the existing materials and systems. 
According to the journal’s website, the first issue of Nature was published in November 1869, making 2019 Nature’s 150th anniversary year. “The history of Nature mirrors how science and its role in society have changed over that time. Here, we are collecting articles that reflect the past, present and future of Nature, as well as that of the global research community we serve”.
Nature Perspective articles are intended to provide a forum for authors to discuss models and ideas from a personal viewpoint and are to be more forward looking and/or speculative.  
To learn more about Duan’s research, visit his group’s website
Penny Jennings, UCLA Department of Chemistry & Biochemistry,