By Dr. Yu-Ming Lin, VP of Bluestone Global Tech
Edited By Will Soutter
Topics Covered
About Graphene
Comparison of Graphene with Bulk Semiconductors
Graphene Production at Bluestone Global Tech
Applications of Large-Area Graphene
Summary
About Bluestone Global Tech
About Graphene
Graphene is the thinnest material in the world. Each sheet of graphene is a single layer of carbon atoms, just 0.34 nm thick, formed in a chicken-wire structure. This two-dimensional nature of graphene leads to a number of unique electrical and optical properties, which have produced enormous interest in the academic and industrial communities ever since it was first physically isolated in 2004.
Some of the important properties of graphene are summarized as follows:
- Highly transparent across the entire visible spectrum with a 97.7% optical transmittance
- High electrical conductivity
- Excellent thermal conductivity
- Flexible
- Chemically stable
- Mechanically robust
Comparison of Graphene with Bulk Semiconductors
Table 1. A comparison of some key parameters for graphene and a range of common bulk semiconductors
| |
Si |
GaAs |
In.53Ga.47As |
InAs |
InSb |
Graphene |
Electron mobility
(cm2/Vs) at n = 1012 cm-2 |
600 |
4,600 |
7,800 |
20,000 |
30,000 |
25000(flake)
~3000(epitaxial)
~2000(CVD) |
| Electron saturation velocity (107 cm/s) |
1 |
1.2 |
0.8 |
3.5 |
5 |
8 |
| Ballistic mean free path (nm) |
28 |
80 |
106 |
194 |
226 |
400 |
| Band-gap (eV) |
1.12 |
1.42 |
0.72 |
0.36 |
0.18 |
0 |
The planar atomic structure of graphene creates a truly two-dimensional system, leading to unique electronic properties. Graphene is effectively a semi-metal, or zero bandgap semiconductor, in which electrons move as massless Dirac fermions at a blazing speed of 1/300 of the speed of light. This exceptional carrier mobility makes graphene an promising candidate for high-speed electronics. While the lack of band gap in graphene may limit its use in digital computing circuits, there are no such restrictions for analog devices and circuits where the device does not need to be turned off.
The superb electrical properties, combined with graphene’s ultimate thinness, high mechanical strength, flexibility and optical transparency, differentiate gaphene from all other semiconductors known to date, and further open up exciting possibilities for novel electronic applications.
Figure 1. Emergent applications of graphene.
Graphene Production at Bluestone Global Tech
Despite all the exciting possibilities enabled by graphene, one of the key challenges in realizing the full potential of graphene is the lack of high-quality graphene films at industrial production scale.
To address this deficiency and to bring graphene to enhance our life, Bluestone has developed a robust method for manufacturing large-area graphene sheets by chemical vapor deposition (CVD).
In 2012, Bluestone announced the production of single continuous graphene sheets over 60 inches (150 cm) across and demonstrated transfer of this large-area graphene onto a flexible PET substrate. It is the first time a single-layer of atoms of such large area was successfully manipulated and handled.
Bluestone has further developed the capability to synthesize and transfer large-area CVD graphene onto a wide range of substrates, including PET and glass. We are developing mass production tools that will allow for lower cost and higher yield of graphene products, along with the necessary quality and process control systems. Our recent development allows for the synthesis of continuous graphene films above 300” in length.
Figure 2. Development of Bluestone Global Tech’s large area graphene film synthesis.
Bluestone's graphene films are quality-controlled to meet the demand of a variety of applications:
- Gratom™-M: high carrier mobility (>3500 cm2/Vs)
- Gratom™-R: low sheet resistance (<150 ohm)
- Gratom™-S: single domain graphene (>200 µm)
- Gratom™-A: large-area graphene with lengths above 7m
Figure 3. Characteriztion of Bluestone’s high-quality graphene products.
Applications of Large-Area Graphene
The availability of high-quality, large-area graphene has generated a great deal of interest from companies and device manufactures seeking solutions to ITO (Indium-doped Tin oxide) replacement. With the proliferation of personal mobile devices and the trend towards flexible electronics, it is expected that graphene will play an important role as a transparent conductor in applications where flexibility and transparency is desired.
With the improving control on graphene quality, it is expected that high-speed graphene devices will emerge to take advantage of the superb electrical properties of graphene. IBM has already demonstrated a graphene-based integrated circuit operating at 10GHz as a frequency mixer.
While there are plenty of applications proposed for graphene, applications that take full advantage of the potential of graphene are yet to be revealed. When more revolutionary applications are developed, there will be no shortage of high-quality graphene material.
Figure 4. Graphene applications in flexible electronics.
Figure 5. A graphene transistor and integrated circuit (IC) developed by IBM.
Summary
Quality-assured, large-area graphene is now available from Bluestone Global Tech for both fundamental research and application or product development.
We welcome strategic partnerships to develop graphene mass-production and processing tools, as well as applications for graphene-based devices.
About Bluestone Global Tech
Bluestone Global Tech (BGT), established in 2011 and based in New York, is the first company to produce high-quality, large-area graphene in commercial volumes. Bluestone's revolutionary graphene products, exclusive processing IP and advanced application development were created to enable concerted enhancements to our everyday lives.
With the mass production of this breakthrough material, Bluestone Global Tech is quite literally redifining everything!
This information has been sourced, reviewed and adapted from materials provided by Bluestone Global Tech.
For more information on this source, please visit Bluestone Global Tech.