'Direct writing' of diamond patterns from graphite a potential technological leap

November 05, 2014

WEST LAFAYETTE, Ind. - What began as research into a method to strengthen metals has led to the discovery of a new technique that uses a pulsing laser to create synthetic nanodiamond films and patterns from graphite, with potential applications from biosensors to computer chips.

"The biggest advantage is that you can selectively deposit nanodiamond on rigid surfaces without the high temperatures and pressures normally needed to produce synthetic diamond," said Gary Cheng, an associate professor of industrial engineering at Purdue University. "We do this at room temperature and without a high temperature and pressure chamber, so this process could significantly lower the cost of making diamond. In addition, we realize a direct writing technique that could selectively write nanodiamond in designed patterns."

The ability to selectively "write" lines of diamond on surfaces could be practical for various potential applications including biosensors, quantum computing, fuel cells and next-generation computer chips.

The technique works by using a multilayered film that includes a layer of graphite topped with a glass cover sheet. Exposing this layered structure to an ultrafast-pulsing laser instantly converts the graphite to an ionized plasma and creates a downward pressure. Then the graphite plasma quickly solidifies into diamond. The glass sheet confines the plasma to keep it from escaping, allowing it to form a nanodiamond coating.

"These are super-small diamonds and the coating is super-strong, so it could be used for high-temperature sensors," Cheng said.

Research findings are detailed in a paper that appeared online in the Nature journal Scientific Reports. The paper was authored by former Purdue doctoral students Yuefeng Wang, Yingling Yang, Ji Li and Martin Y. Zhang; postdoctoral research associate Jiayi Shao; doctoral students Qiong Nian and Liang Tang; and Cheng.

The researchers made the discovery while studying how to strengthen metals using a thin layer of graphite and a nanosecond-pulsing laser. A doctoral student noticed that the laser was either causing the graphite to disappear or turn semi-transparent.

"The black coating of graphite was gone, but where did it go?" Cheng said.

Subsequent research proved the graphite had turned into diamond. The Purdue researchers have named the process confined pulse laser deposition (CPLD).

The research team confirmed that the structures are diamond using a variety of techniques including transmission electron microscopy, X-ray diffraction and the measurement of electrical resistance.

A U.S. patent application has been filed on the concept through the Purdue Office of Technology Commercialization. More research is needed to commercialize the technique, Cheng said.
-end-
Writer: Emil Venere, 765-494-4709, venere@purdue.edu

Source: Gary J. Cheng, 765-494-5436, gjcheng@purdue.edu

IMAGE CAPTION:

This illustration depicts a new technique that uses a pulsing laser to create synthetic nanodiamond films and patterns from graphite, with potential applications from biosensors to computer chips. (Purdue University image/Gary Cheng)

A publication-quality photo is available at http://news.uns.purdue.edu/images/2014/cheng-nanodiamond.jpg

ABSTRACT

Direct Laser Writing of Nanodiamond Films from Graphite under Ambient Conditions
Qiong Nian, Yuefeng Wang, Yingling Yang, Ji Li, Martin Y. Zhang, Jiayi Shao, Liang Tang & Gary J. Cheng
Purdue University

Synthesis of diamond, a multi-functional material, has been a challenge due to very high activation energy for transforming graphite to diamond, and therefore, has been hindering it from being potentially exploited for novel applications. In this study, we explore a new approach, namely confined pulse laser deposition (CPLD), in which nanosecond laser ablation of graphite within a confinement layer simultaneously activates plasma and effectively confine it to create a favorable condition for nanodiamond formation from graphite. It is noteworthy that due to the local high dense confined plasma created by transparent confinement layer, nanodiamond has been formed at laser intensity as low as 3.7 GW/cm2, which corresponds to pressure of 4.4 GPa, much lower than the pressure needed to transform graphite to diamond traditionally. By manipulating the laser conditions, semi-transparent carbon films with good conductivity (several kΩ/Sq) were also obtained by this method. This technique provides a new channel, from confined plasma to solid, to deposit materials that normally need high temperature and high pressure. This technique has several important advantages to allow scalable processing, such as high speed, direct writing without catalyst, selective and flexible processing, low cost without expensive pico/femtosecond laser systems, high temperature/vacuum chambers.

Purdue University

Related Plasma Articles from Brightsurf:

Plasma treatments quickly kill coronavirus on surfaces
Researchers from UCLA believe using plasma could promise a significant breakthrough in the fight against the spread of COVID-19.

Fighting pandemics with plasma
Scientists have long known that ionized gases can kill pathogenic bacteria, viruses, and some fungi.

Topological waves may help in understanding plasma systems
A research team has predicted the presence of 'topologically protected' electromagnetic waves that propagate on the surface of plasmas, which may help in designing new plasma systems like fusion reactors.

Plasma electrons can be used to produce metallic films
Computers, mobile phones and all other electronic devices contain thousands of transistors, linked together by thin films of metal.

Plasma-driven biocatalysis
Compared with traditional chemical methods, enzyme catalysis has numerous advantages.

How bacteria protect themselves from plasma treatment
Considering the ever-growing percentage of bacteria that are resistant to antibiotics, interest in medical use of plasma is increasing.

A breakthrough in the study of laser/plasma interactions
Researchers from Lawrence Berkeley National Laboratory and CEA Saclay have developed a particle-in-cell simulation tool that is enabling cutting-edge simulations of laser/plasma coupling mechanisms.

Researchers turn liquid metal into a plasma
For the first time, researchers at the University of Rochester's Laboratory for Laser Energetics (LLE) have found a way to turn a liquid metal into a plasma and to observe the temperature where a liquid under high-density conditions crosses over to a plasma state.

How black holes power plasma jets
Cosmic robbery powers the jets streaming from a black hole, new simulations reveal.

Give it the plasma treatment: strong adhesion without adhesives
A Japanese research team at Osaka University used plasma treatment to make fluoropolymers and silicone resin adhere without any adhesives.

Read More: Plasma News and Plasma Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.