科学网-张晗的博客-石墨烯锁模得到Geim组的关注了
鏈€鏂版棩蹇?/td>
/01-06
/12-25
/12-23
/12-21
/12-21
/11-17
/10-10
/10-06
/10-06
/09-18
/01-03
/01-02
/12-30
/12-30
/12-26
/12-28
/12-28
/12-25
/12-24
/12-23
/12-18
/11-30
/11-06
/10-19
/10-16
/01-08
/10-15
/10-15
/10-15
/09-10
鍙嬫儏閾炬帴
/
/
/
/
姝f枃
<<

瀛﹁€呭紶鏅?鍙戣〃浜?009-12-23 11:20:47
锛? 鈹? 娴忚锛?118      

鐭冲ⅷ鐑攣妯″緱鍒癎eim缁勭殑鍏虫敞浜?/span>

Graphene - one layer of carbon atoms arranged in a hexagonal lattice - is the newest member in the family of carbon allotropes. Although isolated graphene was reported for the first time only in 2004, the progress it made over these years is enormous, and it rightly has been dubbed "the wonder material".

There are three major areas of excitement about graphene. Firstly, it is the first example of two-dimensional atomic crystal, which very existence improves our understanding about thermodynamic stability of low-dimensional systems. Secondly, the electronic properties of graphene are very peculiar: electrons in graphene obey linear dispersion relation (just like photons), thus mimicking massless relativistic particles. And the last but not least, many properties of graphene are superior to those in all other materials, so it is very tempting to use it in a variety of applications, ranging from electronics to composite materials.

Historically, it is the electronic properties which attracted most of attention. Electrons in graphene behave like massless relativistic particles, which governs most of its electronic properties. Probably one of the most spectacular consequences of such unusual dispersion relation is the observation of half-integer Quantum Hall Effect and the absence of localisation. The later might be very important for graphene-based field effect transistors.

Generally crystals of graphene could be prepared with very few defects (consequence of ultra strong carbon-carbon bonds), which, in conjunction with the absence of localisation and high Fermi velocity ensures very high mobility of the charge carriers and short time of flight in ballistic regime. First prototypes of high-frequency transistors have been recently developed and demonstrated very encouraging characteristics.

Also peculiar are graphene's optical properties. It has been measured that graphene absorbs 2.3% of light - quite a sizable fraction for an ultimately thin material. What is even more exciting is the fact that this number is given solely by the combination of fundamental constants: πα (π=e2/hc≈1/137 is the fine structure constant). Do it at home, multiply 3.14… by 1/137 and you will get something close to 0.023.

Such combination of high conductivity (sheet resistance of doped graphene can be as low as 10 Ohm) and low light adsorption makes this material an ideal candidate for transparent conductive coating. Graphene utilisation for this type of applications has been recently demonstrated by constructing graphene-based liquid crystal and solar cells.

Furthermore, the general issue of graphene mass-production (until recently only research-size graphene samples have been available) has been resolved for these sort of applications with the introduction of a novel technique: large area thin films of micrometer-size graphene flakes can be produced by chemical exfoliation of graphite.

It is very tempting to use the unique properties of graphene for applications. The already mentioned examples do not even nearly exhaust the list of technologies which would benefit from using graphene. Composite materials and photodetectors, support for bio-objects in TEM and mode-lockers for ultrafast lasers - all those and many more areas would gain strongly from using graphene.

The issue, however, was always the mass-production of this material. Since the very first experiments, the technique of choice for graphene production for many researchers was the very naïve "Scotch-tape method", - simple peeling of graphene monolayers from bulk graphite with an adhesive tape. However, recent months seen a dramatic progress in development of truly mass-production techniques for graphene synthesis. Ranging from aforementioned chemical exfoliation to epitaxial growth (for a review see), these techniques give us a realistic hope that soon we will see products based on this exciting two-dimensional material.


1. Novoselov, K. S., Geim, A. K., Morozov, S. V., Jiang, D., Zhang, Y., Dubonos, S. V., Grigorieva, I. V. & Firsov, A. A. "Electric Field Effect in Atomically Thin Carbon Films" Science 306, 666-669 (2004).
2. Geim, A. K. & Novoselov, K. S. "The Rise of Graphene" Nature Mater. 6, 183-191 (2007).
3. Yu-Ming Lin, Keith A. Jenkins, Alberto Valdes-Garcia, Joshua P. Small, Damon B. Farmer & Phaedon Avouris, "Operation of Graphene Transistors at Gigahertz Frequencies" Nano Lett., 9 (1), 422-426 (2009).
4. R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, N. M. R. Peres, & A. K. Geim "Fine Structure Constant Defines Visual Transparency of Graphene" Science 320, 1308 (2008).
5. Peter Blake, Paul D. Brimicombe, Rahul R. Nair, Tim J. Booth, Da Jiang, Fred Schedin, Leonid A. Ponomarenko, Sergey V. Morozov, Helen F. Gleeson, Ernie W. Hill, Andre K. Geim, & Kostya S. Novoselov "Graphene-Based Liquid Crystal Device" Nano Letters 8(6) 1704 - 1708 (2008).
6. X. Wang, L. Zhi, & K. Mullen, "Transparent, conductive graphene electrodes for dye-sensitized solar cells" Nano Letters 8(1), 323-327 (2008)
7. A. K. Geim "Graphene: Status and Prospects" Science 324, 1530-1534 (2009).

Copyright AZoNano.com, Dr. Kostya Novoselov (University of Manchester)

Date Added: Nov 29, 2009
鏈枃寮曠敤鍦板潃锛?
褰撳墠鎺ㄨ崘鏁帮細2    鎺ㄨ崘浜猴細    
[6] 鏍囬锛?/td>
鍙戣〃璇勮浜猴細 [2009-12-24 18:29:27]   
浣犱滑宸ヤ綔鐪熷嚭鑹插晩鍋氫簡寰堝鍓嶆部鐨勯鍩燂紝浣╂湇鍟?br>鍗氫富鍥炲锛氳繖娆℃垜涔熷彧鏄惌鍥藉ぇ椴嶅笀鍏勭殑椤洪杞︼紝涓€璧风爺绌剁煶澧ㄧ儻銆傛垜寰楁劅璋㈤矋甯堝厔锛屾鍥犱负浠栦滑鍋氬墠娌跨殑棰嗗煙锛屾墠鎶婃垜浠甫杩涙潵鐨勩€傚懙鍛碉紝浣犳槸鍋氱煶澧ㄧ儻鐞嗚鐮旂┒鐨勫悧锛熷挶鏈夋満浼氬澶氫氦娴侊綖锝?br>
[2] 鏍囬锛?/td>
鍙戣〃璇勮浜猴細 [2009-12-23 11:31:45]   
鍙戣〃璇勮浜猴細caxinra [2009-12-23 11:26:58] 鍒犻櫎 鍥炲
浠栦滑寰楀紩鐢ㄤ綘浠殑璁烘枃鎵嶈锛屼綘浠槸鍘熷垱锛屼笉鐢ㄥお鎷呭績浜嗗懙鍛?br> 鍗氫富鍥炲锛氬锛屾槸鍘熷垱锛屼笉鐢ㄦ媴蹇冨紩鐢?br> 鑳芥壘鍒扮煶澧ㄧ儻鏂扮殑搴旂敤锛屾浖褰绘柉鐗圭煶澧ㄧ儻缁勫簲璇ヤ細寮€蹇冿紒锛?
鍙戣〃璇勮锛?/td>
鐢ㄦ埛鍚嶏細 蹇呭~
鐢靛瓙閭锛?/td>  
楠岃瘉鐮?/span>锛?input name="Right_content1$txtvalidate" type="text" id="Right_content1_txtvalidate" onfocus="javascript:document.getElementById('Image1').src='blogCode1.aspx?f=13&'+Math.random();document.getElementById('Image1').style.display=''" /> 鍒锋柊 
 
郑重声明:资讯 【科学网-张晗的博客-石墨烯锁模得到Geim组的关注了】由 发布,版权归原作者及其所在单位,其原创性以及文中陈述文字和内容未经(企业库qiyeku.com)证实,请读者仅作参考,并请自行核实相关内容。若本文有侵犯到您的版权, 请你提供相关证明及申请并与我们联系(qiyeku # qq.com)或【在线投诉】,我们审核后将会尽快处理。
—— 相关资讯 ——