2D Material h-BCN

PSPINS Author

07/31/2017 Added

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Vlog describing the MRSEC PSPINS cutting edge research in creating the 2D material h-BCN.

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[00:00:01.738]What I like about this project
[00:00:03.467]is that it is a very good example
[00:00:05.395]that shows how quantity yields a new quality.
[00:00:10.062](soft music)
[00:00:18.087]What I mean, is that after many years of research
[00:00:21.275]by the scientific community on 2D materials,
[00:00:23.990]it was now us who were fortunate enough
[00:00:25.950]to make this milestone discovery of a new 2D material
[00:00:29.848]which will have semi-conducting properties.
[00:00:32.920](gentle music)
[00:00:38.594]Now a days, electronics are a big deal, right,
[00:00:40.533]we have our phones, TVs, tablets,
[00:00:42.414]but they're limited in a fact that they're very rigid,
[00:00:45.525]right, because they are all based on a material
[00:00:47.771]called silicon which is great, but it is very brittle.
[00:00:50.204]You give it a little bit of pressure,
[00:00:52.011]it cracks and it breaks.
[00:00:53.463]What we're trying to do now is move
[00:00:55.172]from silicon based things to organics.
[00:00:57.821]There are a lot of pros to using organics
[00:00:59.552]but the cool thing is that you kind of break
[00:01:01.777]this dependency on having to have something rigid
[00:01:04.129]like a tablet or a phone where you now move from electronics
[00:01:07.537]being rigid and straight to being able to be
[00:01:10.043]flexible and bendable so you can do anything
[00:01:11.760]from having TVs that you pull down,
[00:01:14.015]that are wallpapers that you can put up
[00:01:15.361]and pull down, like a piece of paper.
[00:01:16.580]You can have things like wearables,
[00:01:18.001]like watches or bracelets that can wrap around
[00:01:20.132]and can have electronics all throughout the entire thing.
[00:01:22.570]So, you gain a lot of flexibility
[00:01:24.105]literally from moving from traditional silicon based
[00:01:27.435]computing to organics.
[00:01:29.068](upbeat music)
[00:01:34.091]There's a really famous material that was made a while ago,
[00:01:36.222]got a Nobel prize, got a lot of attention in the field,
[00:01:38.711]and that was graphene.
[00:01:39.639]It's almost like a single layer of just carbon atoms,
[00:01:41.319]that's all it is, and it's a really good conductor.
[00:01:43.124]So, like copper, it conducts electricity really easily.
[00:01:45.630]And then, there have been other materials being made,
[00:01:47.424]another famous one being nanomesh,
[00:01:49.163]it's made out of boron and nitrogen
[00:01:50.756]and that one does not conduct electricity very well.
[00:01:53.377]So, in graphene, it is a good conductor but you cannot
[00:01:56.442]control the current so, once the current flows,
[00:01:58.810]you cannot switch it on and off whenever you want.
[00:02:01.597]With the boron nitride, it's an insulator
[00:02:03.494]so you need a very, very high voltage
[00:02:05.637]or a lot of energy to use it in devices
[00:02:08.840]which is not good from an efficiency point of view.
[00:02:11.298]So, something like copper,
[00:02:12.678]you can flow electricity through it really easily,
[00:02:14.034]that's why a wire is made out of it
[00:02:15.339]and then something like rubber or wood,
[00:02:16.682]electricity doesn't flow very well through it at all.
[00:02:18.632]So, on one hand, we have graphene, which is like copper,
[00:02:20.974]conducts really well, and then we have nanomesh,
[00:02:23.307]which is a boron nitride and that conducts
[00:02:25.350]really poorly like rubber.
[00:02:26.610]So, we have these two main 2D materials
[00:02:28.587]so, that's cool that we have both ends of the extreme
[00:02:31.026]but we're missing a really important middle ground
[00:02:33.358]and that is a semiconductor.
[00:02:34.891]So, it's a little bit of both.
[00:02:36.274]It can conduct electricity sometimes and sometimes not.
[00:02:38.379]The outcome of that depends on what you do to it
[00:02:39.675]and this is the basis for almost all computing, silicone,
[00:02:42.440]so, your phones, your computers,
[00:02:43.554]they all run on semiconductors,
[00:02:45.512]so this material is extremely important
[00:02:47.307]therefore it's a very obvious absence in 2D materials.
[00:02:50.341]We set out to remedy this and introduce a 2D material.
[00:02:53.422]So, we weren't the first to notice this absence
[00:02:56.263]of a semiconducting 2D nano material.
[00:02:58.827]So, many people have been trying to make this.
[00:03:00.498]And kind of the most obvious way to make it,
[00:03:02.907]if we talk about our two previous materials before,
[00:03:04.904]which is graphene, which is all C, and the nanomesh,
[00:03:07.256]which is all B and Ns, is to simply mix them together.
[00:03:10.318]Mix your Bs, your Ns and your Cs all together
[00:03:12.325]and then hopefully you'll get a Goldilocks effect
[00:03:14.377]where you get something in the middle.
[00:03:15.694]Not all the way non-conducting, not all the way conducting.
[00:03:17.682]They're all really cool experiments,
[00:03:19.146]they got cool things out of it
[00:03:20.149]but none of them truly made a 2D,
[00:03:22.606]perfectly patterned, nicely made material.
[00:03:25.794](upbeat music)
[00:03:30.102]We teamed up with some theorists and some chemists
[00:03:32.944]to try to make this ideal small puzzle piece,
[00:03:36.352]or Lego piece, and the idea was that,
[00:03:38.293]if you could throw this on a surface,
[00:03:40.240]that these pieces would connect
[00:03:41.854]in perfectly different ways and they would snap together
[00:03:44.571]to make a bigger picture of 2D material.
[00:03:46.606]So, we were making small building blocks,
[00:03:48.152]small little Lego pieces, that would snap together
[00:03:50.360]at unique sites and then make perfectly uniform 2D material
[00:03:55.878]that would have Bs, Cs and Ns in it in certain positions
[00:03:59.000]'cause we fabricated them to be that way.
[00:04:01.006]So, for that we used metal substrate.
[00:04:02.965]In this case, we used high purity iridium or rhodium crystal.
[00:04:09.108]In order to link these molecules together
[00:04:11.302]we need heat as a driving force
[00:04:13.745]or energy as a driving force.
[00:04:15.924]So, we heat our substrate to close to
[00:04:18.295]a thousand degrees Celsius temperature.
[00:04:20.208]We shoot these molecules in the vapor form
[00:04:23.693]onto the surface of that metal.
[00:04:25.864]So now we've made our material,
[00:04:27.400]but we need a way to prove and see that it exists.
[00:04:30.315]So, if you want to look at the atomic structure
[00:04:32.341]of the material, you need something that has a
[00:04:34.760]resolution where you can see individual atoms
[00:04:37.506]and you can see how they are arranged
[00:04:39.167]in a particular structure.
[00:04:40.658]So, scanning tunneling microscopy is the technique
[00:04:42.712]which can provide you such a resolution.
[00:04:45.091]So, for example, with an optical microscope,
[00:04:47.618]you have a resolution where you can see details of the cell
[00:04:50.930]but if you want to go beyond that
[00:04:52.283]you have to use something different.
[00:04:54.395]We use a technique called scanning tunneling microscopy.
[00:04:57.688]We are able, using this, to actually visually see
[00:05:00.933]atomically small structures.
[00:05:03.236]So, in this technique, we take a metal wire,
[00:05:06.855]which is very sharp, when we bring it close to our material
[00:05:10.719]and we apply a very small voltage
[00:05:13.014]between the material and the tip,
[00:05:14.502]so it gives enough energy to the system
[00:05:16.678]so that the electrons from the material,
[00:05:18.406]they jump between the material and the tip
[00:05:20.671]and by moving the tip over the material
[00:05:23.619]we get a map of how many electrons
[00:05:25.829]are traveling between the material and the tip.
[00:05:27.318]So, using that map we can actually create
[00:05:30.292]a real image to see how these atoms,
[00:05:32.377]which are boron, carbon and nitrogen,
[00:05:34.777]how they are arranged in a pattern.
[00:05:36.992]We believe that this discovery will stimulate
[00:05:40.095]lots of follow up research activity
[00:05:42.553]by our colleagues, by the scientific community
[00:05:45.308]and all that will help establish the material
[00:05:47.449]as a candidate for new electronics applications
[00:05:50.031]that might be thinner, more flexible
[00:05:52.366]and more energy efficient.
[00:05:54.175](upbeat music)
[00:06:01.402]I'm Axel Enders, the fearless leader of this project.
[00:06:04.179]I am an adjunct professor at the University of Nebraska
[00:06:07.058]in Lincoln and I'm also a full professor
[00:06:08.710]at the University of Bayreuth in Germany.
[00:06:11.263]Sumit Beniwal, post doc at
[00:06:13.058]University of Nebraska, Lincoln.
[00:06:14.766]I've been working on this project for three years.
[00:06:17.080]My name is Paulo Costa, I'm a graduate student
[00:06:19.769]at UNL, I've been on this project for three years.
[00:06:22.303](upbeat music)
[00:06:25.548][Female Announcer] Now that's nano.
[00:06:27.024](jingly music)

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2D Material h-BCN

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