10-04 :: April 2010

nanotimes

News in Brief

41

To make a graphene thin film, Berkeley researchers (a) evaporated a thin layer of copper on a dielectric surface; (b) then used CVD to lay down a graphene film over the copper. (c) The copper dewets and eva- porates leaving (d) the graphene film directly on the dielectric substrate. © Yuegang Zhang/LBL

(a) Optical image of a CVD graphene film on a copper layer showing the finger morphology of the metal; (b) Raman 2D band map of the graphene film between the copper fingers over the area marked by the red square on left.© Yuegang Zhang/LBL

“Further improvement on the control of the de- wetting and evaporation process could lead to the

direct deposition of patterned graphene for large- scale electronic device fabrication, Zhang says.

“This method could also be generalized and used to deposit other two-dimensional materials, such as boron-nitride.”

Even the appearance of wrinkles in the graphene films that followed along the lines of the dewetting shape of the copper could prove to be beneficial in the long-run. Although previous studies have indica- ted that wrinkles in a graphene film have a negative impact on electronic properties by introducing strains that reduce electron mobility, Zhang believes the wrinkles can be turned to an advantage.

“If we can learn to control the formation of wrin- kles in our films, we should be able to modulate the resulting strain and thereby tailor electronic proper- ties,” he says.

“Further study of the wrinkle formation could also give us important new clues for the formation of gra- phene nanoribbons.”

Ariel Ismach, Clara Druzgalski, Samuel Penwell, Adam Schwartzberg, Maxwell Zheng, Ali Javey, Jeffrey Bokor and Yuegang Zhang: Direct Chemical Vapor Deposition of Graphene on Dielectric Surfaces, In: Nano Letters ASAP, April 2, 2010, DOI:10.1021/nl9037714: http://dx.doi.org/10.1021/nl9037714 Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87