Editor’s note: The following press release, originally issued by Columbia Engineering, describes a new technique that uses DNA to direct the assembly of electronic devices. This work leveraged two U.S. Department of Energy (DOE) Office of Science user facilities at DOE’s Brookhaven National Laboratory — the Center for Functional Nanomaterials (CFN) and the National Synchrotron Light Source II (NSLS-II). At CFN, researchers used the Materials Synthesis and Characterization and Electron Microscopy facilities to fabricate and study these novel devices. Using the Hard X-ray Nanoprobe (HXN) beamline at NSLS-II, researchers characterized the devices’ nanoscale structure. This research was led by Oleg Gang, leader of the Soft and Bio Nanomaterials Group at CFN and professor at Columbia Engineering. For more information on Brookhaven’s involvement, contact Danielle Roedel (droedel@bnl.gov, 631-344-2347) or Peter Genzer (genzer@bnl.gov, 631-344-3174).
Researchers at Columbia Engineering have for the first time used DNA to help create 3D electronically operational devices with nanometer-size features.
“Going from 2D to 3D can dramatically increase the density and computing power of electronics,” said corresponding author Oleg Gang, professor of chemical engineering and of applied physics and materials science at Columbia Engineering and leader of the Center for Functional Nanomaterials’ Soft and Bio Nanomaterials Group at Brookhaven National Laboratory.
The new manufacturing technique could also contribute to the ongoing effort to develop AI systems that are directly inspired by natural intelligence.
“3D electronic architectures that imitate the natural 3D structure of the brain may prove enormously more effective at running brain-mimicking artificial intelligence systems than existing 2D architectures,” Gang said. The researchers detailed their findings March 28 in the journal Science Advances.
From etching to folding
Conventional electronics rely on flat circuitry. To help microchips grow more powerful, researchers worldwide are experimenting with approaches to building them in three dimensions.
However, current electronics manufacturing techniques are top-down in nature — a piece of material is gradually eroded, for example, by an electron beam, until the desired structure is achieved, like sculpting a block of stone. These methods have encountered problems fabricating 3D devices when it comes to creating complex structures and doing so in a cost-effective manner. For instance, they face challenges in assembling multiple layers of circuitry that stack up properly. “Over the course of hundreds of steps during production, errors accumulate that are prohibitive from the point of view of performance and cost,” Gang said.
A conceptually different way to build a 3D system is from the bottom up, where many components self-assemble into complex structures. Now Columbia Engineering researchers have developed a new biologically inspired bottom-up way for 3D electronics to build themselves. The key behind the new technique is the way in which strands of DNA can fold themselves into shapes — so-called origami. These building blocks, called frames, are then used to assemble large-scale 3D structures, called frameworks, with nanoscale precision.
DNA is made of strings of four different kinds of molecules, known by the letters A, T, C and G. These stick to each other in highly specific ways — A to T, and C to G. By designing multiple molecules with the right sequences, researchers can get long DNA strands to fold themselves into 2D or 3D shapes. Snippets of DNA stapled onto these strands then hold the folded designs in place.
Read more on NSLS-II website
Image: Chip-integrated 3D nanostructured device fabricated using DNA self-assembly (Left panel). A DNA crystal is grown at a designated substrate location (about 1000 crystals on 5μm pads are shown on a Right panel), then mineralized to silica and volumetrically templated with a semiconductor material before electrodes are attached (Center panel). The resulting device exhibits an electrical response when exposed to light. Thousands of such 3D devices can be grown in parallel using this bottom-up fabrication approach.
Credit: Center for Functional Nanomaterials