Rice Lab Uses Laser-Induced Graphene Process to Create Micron-Scale Patterns in Photoresist
May 20, 2021 | Rice UniversityEstimated reading time: 2 minutes
A Rice University laboratory has adapted its laser-induced graphene technique to make high-resolution, micron-scale patterns of the conductive material for consumer electronics and other applications.
Laser-induced graphene (LIG), introduced in 2014 by Rice chemist James Tour, involves burning away everything that isn’t carbon from polymers or other materials, leaving the carbon atoms to reconfigure themselves into films of characteristic hexagonal graphene.
The process employs a commercial laser that “writes” graphene patterns into surfaces that to date have included wood, paper and even food.
The new iteration writes fine patterns of graphene into photoresist polymers, light-sensitive materials used in photolithography and photoengraving. Baking the film increases its carbon content, and subsequent lasing solidifies the robust graphene pattern, after which unlased photoresist is washed away.
Details of the PR-LIG process appear in the American Chemical Society journal ACS Nano.
“This process permits the use of graphene wires and devices in a more conventional silicon-like process technology,” Tour said. “It should allow a transition into mainline electronics platforms.”
The Rice lab produced lines of LIG about 10 microns wide and hundreds of nanometers thick, comparable to that now achieved by more cumbersome processes that involve lasers attached to scanning electron microscopes, according to the researchers.
Achieving lines of LIG small enough for circuitry prompted the lab to optimize its process, according to graduate student Jacob Beckham, lead author of the paper.
“The breakthrough was a careful control of the process parameters,” Beckham said. “Small lines of photoresist absorb laser light depending on their geometry and thickness, so optimizing the laser power and other parameters allowed us to get good conversion at very high resolution.”
Because the positive photoresist is a liquid before being spun onto a substrate for lasing, it’s a simple matter to dope the raw material with metals or other additives to customize it for applications, Tour said.
Potential applications include on-chip microsupercapacitors, functional nanocomposites and microfluidic arrays.
Co-authors are undergraduate John Tianci Li, alumnus Michael Stanford and graduate students Weiyin Chen, Emily McHugh, Paul Advincula, Kevin Wyss and Yieu Chyan of Rice; and alumnus Walker Boldman and Philip Rack, a professor and Leonard G. Penland Chair of Materials Science and Engineering at the University of Tennessee, Knoxville. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.
The Air Force Office of Science Research, the National Science Foundation and the Department of Energy supported the research.
Suggested Items
Suppliers Aim to Raise Contract Prices, But With Uncertain Demand, 2Q24 DRAM Price Increase Expected to Narrow to 3–8%
03/26/2024 | TrendForceTrendForce’s latest report reveals that despite DRAM suppliers’ efforts to trim inventories, they have yet to reach healthy ranges. As they continue to improve their lose situations by boosting capacity utilization rates, the overall demand outlook for this year remains tepid.
Enterprise SSD Industry Hits $23.1 Billion in Revenue in 4Q23, Growth Trend to Continue into Q1 2024
03/07/2024 | TrendForceThe third quarter of 2023 witnessed suppliers dramatically cutting production, which underpinned enterprise SSD prices. The fourth quarter saw a resurgence in contract prices, driven by robust buying activity and heightened demand from server brands and buoyed by optimistic capital expenditure forecasts for 2024.
NAND Flash Industry Revenue Grows 24.5% in Q4 2023, Expected to Increase Another 20% in Q1,
03/06/2024 | TrendForceTrendForce reports a substantial 24.5% QoQ increase in NAND Flash industry revenue, hitting US$11.49 billion in 4Q23. This surge is attributed to a stabilization in end-demand spurred by year-end promotions, along with an expansion in component market orders driven by price chasing, leading to robust bit shipments compared to the same period last year.
India’s Smartphone Market Grew by 1% YoY in 2023 to 146 Million Units
02/13/2024 | IDCAccording to the International Data Corporation ’s (IDC) Worldwide Quarterly Mobile Phone Tracker, India’s smartphone market shipped 146 million smartphones in 2023, with a nominal 1% growth YoY (year-over-year).
Early Price Increase for TV Panels, with a Predicted Rise of US$2–3 for 65-Inch Models in February
02/02/2024 | TrendForceTrendForce research indicates that global TV shipments in 2023 amounted to approximately 195 million units—a 2.7% YoY decrease, setting a new low for the past decade. Looking ahead to the first quarter of 2024, which coincides with the traditional off-season for consumer products, global TV shipments are estimated to decrease by 18.9% QoQ to 43.28 million units.