Korea Institute of Science and Technology

Jae-Kap Lee

So-Hyung Lee

Kwang Yong Eun

Wook-Seong Lee

Seung-Cheol Lee

Jae-Pyoung Ahn

Young Joon Baik

Young-Joon Baik

Phillip John

Jeon-Kook Lee

Bo-Bae Lee

Jin-Sup Won

Disclosed is AA' graphite with a new stacking feature of graphene, and a fabrication method thereof. Graphene is stacked in the sequence of AA&#x2032; where alternate graphene layers exhibiting the AA&#x2032; stacking are translated by a half hexagon (1.23 &#x212b;). AA&#x2032; graphite has an interplanar spacing of about 3.44 &#x212b; larger than that of the conventional AB stacked graphite (3.35 &#x212b;) that has been known as the only crystal of pure graphite. This may allow the AA&#x2032; stacked graphite to have unique physical and chemical characteristics.

AA' stacked graphite

AA' stacked graphite and fabrication method thereof

Disclosed is a method for fabricating graphene ribbons, comprising: preparing a graphitic material comprising stacked graphene helices; and cutting the graphitic material in a short form by applying energy to the graphitic material; and simultaneously or afterward, decomposing the graphitic material into short graphene ribbons. This method provides a mass production route to graphene ribbons.

Method for preparing graphene ribbons

A graphite material and corresponding methods of fabricating the graphite material from graphene nanoribbons are described. The graphite material is composed of a multiplicity of graphene nanoribbons which are randomly layered on each other. The graphene nanoribbons are less than 0.4 nm thick, 5 nm wide, and 20 nm long. One variant of the method of fabricating the graphite material includes preparing graphene nanoribbons, suspending the graphene nanoribbons in a solvent, and then drying the suspension to fabricate the graphite material and to drive off the solvent.

Random graphite and fabrication method thereof using graphene nanoribbon

There is provided a fabrication method for an AA stacked graphene-diamond hybrid material by converting, through a high temperature treatment on diamond, a diamond surface into graphene. According to the present invention, if various types of diamond are maintained at a certain temperature having a stable graphene phase (approximately greater than 1200&#xb0; C.) in a hydrogen gas atmosphere, two diamond {111} lattice planes are converted into one graphene plate (2:1 conversion), whereby the diamond surface is converted into graphene in a certain thickness, thus to fabricate the AA stacked graphene-diamond hybrid material.

AA stacked graphene-diamond hybrid material by high temperature treatment of diamond and the fabrication method thereof

A hollow diamond shell with a size of a few micrometer to hundreds of micrometer and having a geometrical shape and its fabrication method are disclosed. A diamond film is deposited by a CVD method and porous grits are used as a victim substrate to be etched later, so that the substrate can be easily removed by a capillary phenomenon that an etching solution can be intensively absorbed in a substrate etching process. Thus, a perfect diamond shell with only a plurality of fine pores with a nano size without any conspicuous opening can be obtained. Also, a diamond shell with a small opening of below 10 percent of the surface area of grits can be fabricated by controlling a nuclear generation of diamond particles.

Diamond shell fabricated by using porous particle and the fabrication method thereof

The present invention provides a method for depositing self-aligned carbon nanomaterials (carbon nanoflake, carbon nanotube, carbon nanorod and carbon nanosphere), by inducing a gas chemistry for the carbon nanomaterials, on a substrate having a large area of several inches in diameter, under the conventional CVD diamond deposition conditions. The well-aligned carbon nanomaterials on the large area are applicable for sensitive base materials in the fields including biochemistry and electrochemistry.

Method for synthesizing self-aligned carbon nanomaterials on large area

Disclosed are an apparatus and a method to synthesize powders typed diamond with the size between several tens nm to several &#x3bc;m in diameter using conventional CVD processes for deposition of diamond films. Gas phase nucleation has been induced on the boundary of plasmas, and as a result the spherical diamond powders accumulated have been obtained on circumferences of the normal substrate. With a modification of a substrate structure, a large area accumulation of the diamond powders of around 100 mm in diameter has been accomplished.

Apparatus and method for synthesizing spherical diamond powder by using chemical vapor deposition method

The present invention relates to a diamond film synthesizing apparatus, and in particular to an apparatus for increasing the deposition area to several inches in diameter by using multiple cathodes (Multi-cathode DC PACVD). In the multi-cathode DC PACVD apparatus according to the present invention, the basic array of the cathodes is determined so that the uniformity of diamond films on a deposition area is maximized. A seven-cathode structure, in which six cathodes are radially arranged at the same distance of 43 mm surrounding one central cathode, in which a basic unit of the array is regular triangle, is designed for depositing uniform diamond films on a 4&Prime; substrate. Here, the shape of six edge cathodes is rod of which the lateral face is joined to the connecting rod, so that non-uniformity of temperature in the edge cathode is minimized and then the reliability of the apparatus is much enhanced. The multi(7)-cathode DC PACVD apparatus enables one to deposit 4&Prime; diamond films with a thickness uniformity of 3.8% thicker than 1 mm. The unit of the cathode array according to the present invention can be adapted when increasing the deposition area to 8 inches, 12 inches, etc.

Apparatus for synthesizing diamond film by DC PACVD

A method of synthesizing an even free-standing diamond film without growth cracks is disclosed. The intrinsic tensile stress of a diamond film is compensated by an artificial compressive stress with a step down control of the deposition temperature during deposition. After a diamond film is deposited with a predetermined thickness at a deposition temperature, the deposition temperature is decreased in multiple steps during the deposition. The bending of the diamond wafer is minimized by using a tungsten substrate with higher elastic modulus than molybdenum.

Method of synthesizing even diamond film without cracks

An improved diamond film synthesizing apparatus and a method thereof using a direct current glow discharge plasma enhanced chemical vapor deposition advantageously providing a plurality of cathodes for forming a relatively large plasma size, which includes a reactor having an upper wall and a bottom wall; a plurality of spaced apart cathode holders half inserted into the upper wall of the reactor, arranged in a triangle when looking dowawardly over the head of the reactor; a plurality of cathode connecting rods, each of which is threadly connected to the cathode holders inside the reactor, respectively; a plurality of cathodes, each of which is threadly connected to the cathode connecting rods, respectively; an anode half inserted into the bottom wall of the reactor and having a substrate attached on the top thereof, whereby all the cathodes and the anodes are spaced apart inside the reactor by a predetermined distance; and a gas supplier connected to one side wall of the reactor having a circular gas supplying tube having a plurality of holes for injecting gas into the reactor. In addition, the diamond film synthesizing method using a direct current glow discharge plasma enhanced chemical vapor deposition comprises the methods of cutting off the heat transfer from a cathode to a cathode holder, thereby maintaining the temperature of a cathode to be within a predetermined range for a stable production of a plasma.

Growing community of inventors

Seoul, South Korea

Jae-Kap Lee