Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea.
Nanotechnology. 2016 Aug 5;27(31):31LT03. doi: 10.1088/0957-4484/27/31/31LT03. Epub 2016 Jun 27.
In order to utilize the superb electronic properties of graphene in future electronic nano-devices, a dependable means of controlling the transport properties of its Dirac electrons has to be devised by forming a tunable band gap. We report on the ion-induced modification of the electronic properties of single-layer graphene (SLG) grown on a SiC(0001) substrate by doping low-energy (5 eV) Li(+) ions. We find the opening of a sizable and tunable band gap up to 0.85 eV, which depends on the Li(+) ion dose as well as the following thermal treatment, and is the largest band gap in the π-band of SLG by any means reported so far. Our Li 1s core-level data together with the valence band suggest that Li(+) ions do not intercalate below the topmost graphene layer, but cause a significant charge asymmetry between the carbon sublattices of SLG to drive the opening of the band gap. We thus provide a route to producing a tunable graphene band gap by doping Li(+) ions, which may play a pivotal role in the utilization of graphene in future graphene-based electronic nano-devices.
为了在未来的电子纳米器件中利用石墨烯卓越的电子性能，必须通过形成可调带隙来设计一种可靠的控制其狄拉克电子输运性质的方法。我们报告了在 SiC(0001) 衬底上生长的单层石墨烯（SLG）通过掺杂低能（5 eV）锂离子来改变其电子性质。我们发现，通过掺杂低能（5 eV）锂离子可以打开一个相当大且可调谐的带隙，最大可达 0.85 eV，这取决于锂离子剂量以及随后的热处理，并且是迄今为止通过任何手段在 SLG 的π带中报告的最大带隙。我们的 Li 1s 芯能级数据以及价带表明，锂离子不会在最顶层石墨烯层以下嵌入，但会导致 SLG 的碳原子子晶格之间产生显著的电荷不对称性，从而导致带隙的打开。因此，我们提供了一种通过掺杂锂离子来产生可调谐石墨烯带隙的方法，这可能在未来基于石墨烯的电子纳米器件中利用石墨烯方面发挥关键作用。
