 고맙습니다. 저는 이 피지시스와 엔지니어스타일의 연결과 연결을 시작합니다. 저는 어제릴마스와 아안의 프로필서의 연결이 되었습니다. 전 로저의 그룹에 대해 공개합니다. 우리 그룹의 20명의 멤버들과 함께 그룹의 업그레이밍을 매우 힘든 것입니다. 삼성, LG와 LG에 대한 많은 업그레이밍이 있습니다. 그룹의 업그레이밍에 관심이 있습니다. 그룹의 업그레이밍에 많은 좋은 소식이 있습니다. 트랜스파이너로 사용할 수 있습니다. 또한, 월트라펫 트랜지스터를 사용할 수 있습니다. RF-IC, 포토-갯 센서를 사용할 수 있습니다. 에너지 레트로를 사용할 수 있습니다. 투명한 배터리를 사용할 수 있습니다. 컴퍼너로 사용할 수 있습니다. 그리고, 트랜스파이너로 사용할 수 있습니다. LED, 빛깔, 그리고 배터리, 그리고 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, 그리고, red or blue, but graphene is extremely transparent for all range of light wavelengths, which is better for optoelectronic performance. 그래픽이 모든 range의 라인의 웨이블랭스에서 굉장히 흥분한 기술을 더 잘하는 것입니다. 그래서 이 부분에 대해서는 왜 그래픽이 modern technologies에 중요한 것은 그리고 어떻게 그래픽을 기술을 통해 워키모션을 통해 기술을 통해 기술을 통해 그리고 저는 제 수업을 수업할 것입니다. 왜 기술을 배우는 거예요? 물론, 기술은 플렉스러운 기술이니까요. 그리고 이 기술은 수업의 작업과 수업의 일정, 그리고 수업의 공간을 배우는 것입니다. 특히 기술을 배우는 기술이 아주 높은 기술이 있습니다. 그래픽이나 OLED, OTFT, 또는 organic photovoltaic 더 높은 퍼포먼스가 가능할 수 있습니다. 2008-2009년 이 3개의 그룹이 시비디 그룹의 라이스 스케일 그래픽, 폴리스, 크리스탈라, 닉컬을 사용합니다. 닉컬의 그리핀 그룹은 40년 정도의 길을 알 수 있을 것입니다. 이 그룹의 그리핀 그룹은 폴리크리스탈 라인의 닉컬에 인실레이딩 섭취를 통해 첫번째로 FET property를 설정했을 것입니다. 그리고 닉컬의 경우는 많은 레이어드가 아주 어려워질 수 있었지만 그래픽을 사용하면 모노레의 커버리지가 95%가 더 높아질 수 있습니다. 그래서 람암 페이퍼를 볼 수 있습니다. 그래픽을 제거하고 아주 간단한 프로세스입니다. 그리고 아마 이 방법을 그래픽을 제거할 수 있을 것입니다. 이 책에 적용했을 때, 사실 이 컨트롤의 효과는 기술의 그리핀과 커플의 기술의 그리핀에 적용할 수 있습니다. 이 그리핀의 퀄리티의 퀄리티의 기술의 그리핀은 기술의 그리핀에 적용할 수 있습니다. last year we reported the role-tooler production of ultralight-scale graphene using this copper voice. Here we have used polymer support to hold the graphene while we etch away the backside copper layer. And then we transfer graphene onto arbitrary substrate using this simple role-tooler process. So we have used this freedom to fabricate touchscreen like this. And then it works perfectly as I show later. And nowadays we are trying to lower the synthesis temperature using the plasma techniques. Because if you use thousands of temperatures, it's very hard to machine on the chamber. So if we need to, in the case we need to use quartz or ceramic chamber, but if you cool down the growth temperature below 700C, then it is possible to use metallic chamber. So recently we have synthesized graphene on polymer substrate. After deposit nickel layers on top of PI polyimide, and then we grow graphene at 300C. And then if we etch away this nickel layer, actually this is transfer free. Only nickel layers are dissolved in this etching solution. Although the property of graphene is not so good, we can get very uniform filaments at this low temperature growth. And the advantage of this method is that we just pattern all the copper circuits, copper lines on glass or film. And then just by simply growing graphene on top of copper, we can passivate the copper layers. Or you can tune the contact resistance between this copper electrode with the channel materials that can be enhanced, which can be used for the enhancement of the backplane TFT performances. Okay, now we are collaborating with Samsung Tech Queen to realize the continuous production of graphene, combining the ISP-CVD process with this world tour production. I think we are trying to make the pilot line within three years, but the real application depends on the market. So I don't know the future well, but we are trying our best. So recently we supported by the rice group, and we can grow graphene using the solid source. And then sometimes, and the other group also reported, just put the cell percent monolayer under the metal layer, and then if you grow the graphene, then actually the graphene, that CVD graphene is transfer free. And also this actually in this paper, it's shown that the wave scale homogeneous bilayer graphene film can be seen by chemical vapor deposition. But based on my experience, actually I doubt this result, because sometimes we see these multi-layer graphene flowers grown on top of or under the monolayer graphene. And then actually their alignment is not single-crystal line. So if we observe the Raman spectra, although the optical contrast indicates the flower shape, it's kind of bilayer, but their Raman spectra are quite different. Using SKPM, the work function can be measured by SKPM, and then we found that this part is not ab stacked bilayer. So this is twisted bilayer. So I guess it is very hard to get uniformly aligned ab stacked bilayer in wave scale. So I think the wave scale bilayer growth is quite challenging. Okay, then I'd like to show how to enhance sheet distance graphene. There are a few factors for governing the sheet distance property of graphene. So as you probably know, the charge carrier density is proportional to doping level. So if we assume that mobility of few thousand and then at this doping level we can get 100 ohm per scale from monolayers. And many of you are trying to dop graphene with wet chemical method or the iron liquid and something like that. But we have used the ferroelectric polymer to dop the graphene, strongly dop the graphene. So after we put the graphene between this electrode, put the ferroelectric layer between this electrode and if you polarize, actually we can strongly dop the graphene with this ferroelectric polymer. So as we apply graph, the voltage from 50 at 50 volts, 100 volts and 150 volts, the resistance drops almost 10 times. The theoretically the sheet resistance of monolayer is as low as 17 ohm per scale. So if you stack four monolayers, then you can expect the sheet resistance smaller than 10 ohm per scale, which is the ideal for optoelectron applications. So they are even stronger, the ferroelectric materials like PZT. So eventually we can reach 10 to 14 level using this ferroelectric materials. So anyway, if you dop graphene very strongly like this, probably the optical transition between this range is not allowed. So for example, if you dop graphene by one electron volts, so all transition corresponding to red color is blocked. So graphene is transparent to this absorption range. So this means that we can tune the optical transmittance or the absorption of graphene by tuning the gate electric volt or the doping level. So in Berkeley, the Fengen group used this property to realize graphene-based broadband optical modulators. Here the transmission of the graphene was modulated by gate voltage. So in this voltage range, it shows quite large absorption, but in this case, the lights are transmitting the graphene. So this graphene shows very nice optical modulation over very long range of the wavelengths. Also the reflective index of graphene is changing according to the environment. So we can use this. After we caught graphene, after we caught optical fiber with the graphene, then if you tune, if you change the environment, the surroundings, then we can change reflecting this graphene so that you can change total internal reflection inside this optical fiber. So we can use this phenomena to make a graphene-based optical fiber sensor. Okay, so NUS group and then the Cambridge group was reported the use of graphene as a saturable absorber. Then this is very useful for optical communications. And there are more graphene-based Terahertz application useful for the security imaging or defense technologies and I'd like to skip this one. Okay, then nowadays these are the issues for the people who are working on graphene synthesis. So what does limit the conductivity of graphene? That could be grain boundary, ripples or substrate roughness. So I'd like to introduce this one by one. So if you are new to graphene, cut copper foils for an hour, the grain size of the copper foils is larger than a few centimeter scale. And then graphene grows across the grain boundary like this. This means that the growth of graphene on copper is not epitecture. And as you see here, graphene can grow on one-on-one or one-on-zero or in two-zero-zero surface of the copper. So we think that the single crystallinity of copper is not so important to improve the quality of CVD graphene. And in this paper, in this theory paper, they claim that the angles or the periodicity of the grain boundary is very important for the electrical properties of graphene. And actually the Kone group imaged the grain boundary of the graphene using operation-corrected TM techniques. And you can see hexagons and haptagons along these grain boundaries. And they claim that these grain boundaries are not so important for the electrical properties. And then also they mapped the grain size of graphene using this dark field TM techniques and found that the individual grain size is smaller than micrometer scale. But I think in this case, the color of graphene is not so good, but we often see graphene domains larger than millimeter scale. If you carefully control the graphene growth conditions. And in this paper published in Nature material recently by the party group, actually they can grow this hexagonal shape of graphene flakes using the ambient pressure graphene growth. And then they found that this merging along this merging line, actually the grain boundaries are forming and this is 2D peak of the Raman spectra. And then they measure the transport property across the grain boundary and they found that this grain boundary is critical for electrical properties of graphene. But our opinions are a little different. So we also grow graphene on top of this copper and then measure their property. And then we found that there's a strong temperature dependence in this case. This means that there's some additional factor for the electrical purpose of graphene. So as shown in this paper, recently published in PRB, actually they artificially control the morphology of copper and they found that because of the copper roughness and the thermal, negative thermal expansion of the graphene, we often see this multiple force of graphene when we transfer graphene onto the flask of trade. But in this case, the density of this force, just one or two in probably 100 micrometer scale. So this means that if you make a few micrometer large device, this multiple folding is not so important. So you're trying to find a reason for this one. And then you found that if you grow graphene on top of this large stages of copper and then after transfer, the extra surface area from the stages can make this nano rippers. So, and then we try to measure the electrical party of the graphene, along or parallel to perpendicular to the rippers. And then we found that this geometry shows more temperature dependence. So we assumed and the density of this nano rippers are a few in the micrometer scale. So I guess we should see this nano rippers in all the devices based on CBD graphene. So this minimizing the ripple density is very important to control the quality of graphene. This is our story. So the temperature depends on thus our parallel geometry and horizontal geometry and this doping dependence. Then we conclude that the controlling roughness is very important. So if you carefully look at the surface of the copper after the graphene growth. So in this case, there are a lot of, you know, stab edges and in this case, it's almost atomically flat. So if you compare the mobility of the graphene from this flat area and this rough area, this mobility from flat area, graphene from flat area is almost 1.5 times better than this case. So I think this is another evidence for our conclusion. So in this paper recently published in the chemical materials, actually they try to control the roughness of the copper using this electro polishing method. And then they found that the color is much better than that of this rough copper surface. So now we are trying to polish the copper foil with this electro polishing method or mechanical polishing method and then we get enhanced sheet resistance so that this substrate often is extremely important. And as reported by Columbia Group recently, and they claim that the graphene grown on copper one-on-one surface is better than that of graphene on copper one-zero-zero surface. I don't know the reason very well. Probably because of the good lattice matching with graphene with this copper. And so we are trying to control the crystalline orientation of copper using this electroplating method. So if you use royal pressed copper foil, the most of the crystalline orientation is two-zero-zero. But for the electroplated copper, it's mostly one-on-one, which has lower surface energy. So I think you're trying to use this method to get one-on-one dominant surface to enhance the sheet resistance graphene, but we don't have any visors now. This is another evidence of nano-reversed formation. Actually, Barbara's actually first float graphene on top of water, and then transfer this graphene onto this silicon oxide. And then we see no reapers, nano-reapers. This means that nano-reapers can be released or removed when we float a graphene on top of water. So I think this is a very smart, nice way to remove the nano-reapers to get higher quality of graphene. So our conclusion is that the nano-reapers is very crucial, then we need to control the number of surface roughness of copper. And also the substrate is also important. So if you transfer graphene onto this rough PET substrate, the sheet resistance can easily go up to kilo-ohm per square. That means after transfer, some of graphene can be suspended and were broken. So we need to use substrate with the morpholode, whose roughness is smaller than five nanometer. So I guess this is also important. So as you know, if we use bilayer hexagonal boron nitride field, we can enhance sheet resistance graphene. And then because sheet resistance graphene is inversely proportional to the mobility of graphene. So we try to grow large-scale graphene, large-scale hexagonal boron nitride, as suggested by Professor Ajayan group in Rice University. So they are using ammonia borane source like this. And then you can easily decompose into boron and nitrogen source like this. So here we hit this solid source of ammonium borane and then the gas is going to this gross chamber. And then we can grow the large-scale, the boron nitride very easily. And as reported by Ajayan group recently, we can grow graphene, boron nitride on top of graphene. They first grow graphene on top of copper and on top of copper, they claim that they can grow boron nitride epitexially on top of copper, on top of graphene. And actually this, we reproduced the result. This is our image. Surprisingly, the boron nitride is growing very well on top of CBD graphene. And this is hexagonal boron nitride grown on the graphene and then their thickness is ranging from five nanometer to 20 nanometer. This is not single layer. Also as reported in carbon recently, they have used graphene on top of hexagonal boron nitride without using any catalysts. So in this case, it was very hard to reproduce, but we have some evidence that the graphene has formed on top of hexagonal boron nitride. Then what does it mean? So we can actually make superlatives of the boron nitride and graphene by growing graphene in turn. So I think this approach is very important for the future applications of the 2D materials. And so ideally we would like to reach this limit. So 10 ohm per scale at 90% transmittance is kind of critical value for the real applications of graphene. But now graphene is not as good as ITO at the moment, but I guess utilizing this previous approach is possible to overcome this limit in the near future. And finally, I'd like to introduce Warfuxer Engineering for the solar cells. So here by combining graphene with silicon, you can easily make solar cells. But in this case, we need shocky contact. But if you use four-layer graphene, four times transferred graphene, then it makes army contact, which is not good for solar cell effect. So although the conductance of the four-layer graphene is much higher than the monolayer, it doesn't show any photovoltaic effect. Why show the monolayer graphene shows very nice photovoltaic effect. This means that work function training is sometimes more important than the lower, higher conductance of graphene. So we can control the work function using the self-possessing monolayers. This molecules are covalently attached to the silicon oxide, so this is non-volatile. So it's very stable. Then after that, we transfer graphene onto the self-possessing monolayer. By changing the functional group of self-possessing monolayer with electron donating or electron withdrawing group, we can feed up or end up graphene. So after we pattern the self-possessing monolayer, then after we transfer graphene, then we measure the Raman, and then we see strong doping effect from this Raman spectrum. So using this method, we selectively tune the work functions of graphene from this red color to blue color, and then the FET performance can be enhanced. So we can get better mobility and better height performance by tuning this work function's graphene. So graphene is particularly important for the organic devices. So we have used graphene electrode as the electrode source and drain electrode for pentason FETs. As you see here, we can get 100 times smaller contact resistance and more than 10 times higher mobility by using graphene electrodes for the pentason FETs. So graphene is flexible. So it is the perfect material for flexible electronics. And but graphene doesn't have any gap. So in that case, we can combine this with the property of carbon nanotube with very large band gap. So we have used carbon nanotube as channel materials, and then use graphene as source strain and gate. And then we can realize all carbon, you know, the transparent and flexible devices like this. And the onofratio is reasonable. And then so in addition, also we can combine this with the silicon nano ribbon. So very thin silicon materials are very flexible. So this work is done by Professor Ahn. They have used silicon nano ribbon as channel materials and then used graphene for source strain and gate and realize this transparent and flexible devices. And this work is done by Professor Liu Lee in POSTEC and Jonghyun Ahn. And they have used the nitric acid doped graphene to replace ITO materials. And as you see here, the luminous efficiency is 1.5 times better than that of the ITO based devices. Actually we don't know reason exactly. The traditions of ITO is Tynome Buscare. But graphene, its real essence is close to 100 Ohm Buscare. But the performance is better for the graphene devices. I think probably this is because of the work function matching or the better whole injection efficiency. So they and they use this method to make the OLED lighting. So graphene shows very linear response to the strain. So the graphene can be used as a strain gauge. This work is done by Professor Jonghyun Ahn. And so we need also transparent healer for this car windows or the windows of airplane or the helmet, this is de-fogging windows. And graphene shows very nice heating performance as a transparent healer. So I think it's useful in the future. So graphene can be used as thermal spreading materials. So it shows very efficient cooling when it's coated on the metal or any kind of materials. So we demonstrate the use of graphene electrodes for the gallium nitride light emitting devices. And recently Professor Kutcher Lee in Seoul National University to grow the Dinkun nanoroute on top of the graphene without using any catalyst. And then make the multi-shell gallium nitride LED rods and then they demonstrate their light emitting performance is very nice. And then quantum dot can be synthesized by using graphene as the electrochemical templates. And this quantum dots can be combined with graphene and they can be used as the quantum dot LEDs. Recently we are collaborating with the Seoul National University quantum dot LED group and then used graphene as an anode and cathode and then after carefully tuning the size of the quantum dots we realize the blue, green and red emission from quantum dot using graphene as anode and cathode. So as you see here, this light emitting device is very flexible and transparent. So I think it's possible to use graphene is for this transparent displays. Sorry. Oh, this is the graphene OLD lighting based on graphene electrode. Okay, so finally I would like to give you some keys. I would like to ask this question to the youngest scientists in this room. Andres Doher. Okay. What do you expect next? Probably, yeah, most, you can expect carbon nanotube or something like that. But actually I asked the same question to my daughter and it was like this. And so the reason I am showing this one. So if you assume this goal that is graphene and the size of most gas molecules are as large as this football. So you can use graphene as gas barriers. And for the stable operation of organic LED for 10 years we need this water permeation rate, microgram per square meter per day. But there's no material that can reach this performance. So the best one is barracks from DuPont with 10 to negative minus four gram per square meter per day. And they have this very thick inorganic and organic polymers to make this high-performance barrier film. But in the case of graphene, just we have used three layer and six layer graphene and they reached 10 to minus four or five. Even though it is not stable yet I think this is quite promising. So I think we need to control the density of defect and grain boundaries and they need to combine this one with polymers. But anyway, I think this is very useful approach to get high barrier performance based on graphene. So in addition it is recommended that by Apple. So iPhone user need to keep their cell phone at least 15 millimeter away from your body. So because of the electromagnetic radiation from your cell phone. And graphene has very strong electromagnetic interference shielding property over very large range of the wavelengths. So I think we can get 20 to 30% EMI shielding by using graphene films. Actually I'm showing this. I have shown this result two years ago in Korea but there's some progress in this one. So I'd like to introduce the copper replacement using graphene. So as probably know The existing copper reserves available is available mining very from 20 to 60 years. And then most of the copper from these areas and particularly from Chile. And as you see in this figure. So actually copper is not forever. It's not forever. So someday probably the mining of copper will not be more available. So as of since the industrialization the use of copper is increasing exponentially and for the last of years almost 10 times increased. So people are trying to replace this copper with aluminum was superconductors and carbon nanotube but their performance is not as good as copper. So we have tried to use this graphene fiber to replace copper and by controlling hydrophobicity and surface tension the graphene tribe can be suspended in solution like this and then followed by formation of fibers like this. And then we measure their electromechanical property and the electrical property. So there are mechanical properties are a little bit poor than that of aluminum but it shows reasonable value. And so it is very hard to define the diameter of the graphene fiber. Just we just we have used this effective conductivity of graphene fiber based on their density or the density like this if you consider the low density of graphene fiber the conductivity of graphene fiber is better than that of copper. So we didn't dope graphene fiber at all. So I think if you use some doping method and it is possible to get the better performance than the copper. So we have used this graphene fiber for this LED operating at one five volts with the graphene fiber. So it shows linear IV up to 50 volts. So it's quite stable. And then the together with the electrical wire company we are developing this graphene coated electrical wires. This is bare copper nickel coated copper wire and then after on the wire the surface is very rough but after we coat graphene wire it looks very rough but the conductivity can be enhanced up to 50%. So if you look at this TME analysis of graphene coated nickel copper wires and here we see multilayer graphene are formed on top of nickel. So we compare the conductivity of this wire depending on the diameter of copper and nickel copper wire. So in the case of copper wire the larger diameter shows less enhancement but in the case of nickel coated copper wire as the wire diameter increases we could get the better conductivity. As you see here this is saturating somewhere here but anyway conductivity of the copper wire can be enhanced by using this graphene that means that you can use much less copper for the wire with the same capacity or same performance. So I'm working with LS cable the company is world's third largest wire company and they are really serious about this one for the combination of this graphene coated wires and then we design the real-tural and a pilot layout like this. In this case we don't need any transfer just after we prepare the nickel coated copper wire then just we grow graphene using this roll-tural chamber and then that's it. So we can use graphene after insulating this graphene coated wire with polymers. So I think this is very close from the real applications so I think this is good approach. So another good application is the use of graphene lecture for the batteries. Since the spacing between graphene layers are much larger than that of graphite so we can charge this battery 10 times faster than this conventional batteries and also the capacity is much larger than the case with graphite electrode. So many people are working for this graphene based the lithium ion batteries. Okay, finally, I'd like to use these results recently published in ACS nano we collaborate with Barbaros and NUS group and they have used our graphene for to grow the stem cells And as you see here in this case we didn't use inducers and we have used inducers. So without inducers actually in the case of no graphene almost no cells have grown on top of this glass of trade but we don't know the reason very well actually graphene can initiate differentiation of human stem cell to bone cells without inducing any inducers. So I think probably this kind of bio application is very promising in the future. So after you grow graphene on top of this philum just imagine that you can transfer this stem cell to into your body for reconstruction of your bone or the neuron cells. Actually we don't know the safety problem of this graphene yet but I think we need to focus more on this bio application in the future. Okay, this is summary of my presentation and then I expect large scale production and the real commercialization can be realized in your future. But as you see in this movie the future of graphene is very bright but current status is like this. We just realize the use of graphene for this flexible touch screen but there are really many things to do. For example we don't have flexible batteries don't know flexible transistors so I think probably we need to wait probably longer than 10 years or 20 years to see these flexible devices but I guess we need hope, we have a dream. So I guess then graphene will contribute a lot for this flexible electronic application in the future. Okay, thank you for your attention. When you talking about when you grow the graphene on the same ID they have a lot of the repose. Yes. So when you transfer it then it's like strength relieved. Is that due to the thermal expansion between the copper and the graphene different? So we transfer to the other substrate so it will disappear. So actually as shown by the Berkeley group I think the thermal expansion makes multiple folded graphene is a little bit larger than the nano-repress. So we call micro-repress or something like that. And their periodicity is longer than 100 or tens of micrometers. So the reason why that repress is not so important for our devices is that if you make for example 5 micrometer long device there is almost no chance to make device across the repress. So we can exclude the possibility so that we claim that nano-repress are very important. I would like to ask a question about graphene with organic materials, the pentazine. Why would the mobility increase? So the limitation for mobility in organic single crystals is due to frolic polaroids at the interface with dielectrics. Here you are changing the context. Yes, that's very good question. So I didn't show the detailed orientation of the pentazine on graphene. So for pentazine as a channel this vertical stacking is better than this kind of stacking. So if you induce some deep contamination on top of this graphene we can intentionally enhance this vertical stacking so that there's two factors. One is from the contact resistance the other is the change of the crystalline orientation of the pentazine to enhance the mobility. So recently we published the paper in Jax then I'll give you the reference later. You briefly mentioned growing graphene directly onto hexagonal ball nitride substrates. Has anybody thought about the actual mechanism because clearly that isn't catalyzed and it's not by the mechanism you sort of expect from growing directly onto metals? So we don't know the mechanism very well but there's already some report that graphene can be grown on insulating substrates like magnesium oxide or sapphire or something like that. So I guess even on top of copper it was not fully understood. Actually Roth claims is kind of self-relimiting mechanism. The carbon sources are temporarily absorbs on copper and then migrates to make the hexagonal lattice. So I think probably this is similar to that of the... So you think it's the same as similar mechanism to the copper rather than because certainly if you sort of look at other things like nickel you get absorption of it and then precipitation of the carbon out. But I would have thought the copper surface actually acted as a catalyst. So I'm surprised myself but it's requiring an out-surface like that. Yeah, so actually I doubt this result. That's why I try to produce this one but it works. So I don't know. It's very hard to explain. Very hard to explain. I was about to ask a question but maybe I can make a comment about that. About two years ago a group in North Texas University Oh. sent us samples of this Oh, really? or I tried to graphene it. And as I see from this picture it has the same problem, very large D-pink. Yeah. And it just doesn't grow well. But any surface will give you graphene because that's unstable form of carbon provided that you have enough thermal energy to decompose the earth's gas. And people of course now report just about everything or certainly gold and other metals to multi-director. So the catalyst's part is not very strong. Just heat. I wanted to ask a detail. During your talk you saw what you called an anomalous temperature dependence. Yes. If you said there is something else going on I wonder if both electron and hole transport so who's this temperature dependence? Actually we didn't compare carefully. So I think we just measured the temperature dependence on the whole side, I guess. There was a question that was asked yesterday by someone involving electron, phonon, caplic and there are several reports already in the literature where people obtain different deformation potentiates for electron, certain holes. And if you follow that line of research it may lead you to what is going on. Okay, thank you. Thank you for comments. Regarding the coated copper where you coat the copper with graphene do you understand the physical mechanism for the enhancement of the conductivity? Enhancement of conductivity. What's the physics behind this? Physics. So we think that actually if it works when the diameter is very small then usually there is a skin effect of the copper. So even though we use very large diameter copper only surface area of the copper can contribute to the conductivity of the total wires. So if we have graphene on top of copper we have additional channel in addition to the skin of copper. So this is just a very high frequency. It's not that we can't start using this for power cables there. But the power cables even use 70Hz 70Hz AC voltage. So we measured this conductivity, this one. But I cannot say like that. But there is some additional conducting channel through graphene I believe. So you deducted it. Not for conductivity. And then when you put the graphene on water what's the chemical method? The ions out of the ripples. Ripples? Yeah. What does the water do? The water's suspension? I think simply I think simply we have the 4D structure then there's a kind of stress or strain. So on top of water it can naturally release. So yeah, actually we are preparing that as for the referee part. So the referee I don't know Someone in this room is our referee. Is it the best liquid? Or could you use some organic liquid? Would that be better as opposed to water best? Just water. Just on top of water graphene is floating. But in organic solvent actually it sinks.