Electronic Properties of Graphene Encapsulated with Different Two-Dimensional Atomic Crystals
Electronic Properties of Graphene Encapsulated with Different Two-Dimensional Atomic Crystals
复制标题
DOI：
10.1021/nl5006542
复制
发表时间：
2014-06-01
期刊：
影响因子：
10.8
通讯作者：
Gorbachev, R. V.
中科院分区：
文献类型：
--
作者：
Kretinin, A. V.;Cao, Y.;Gorbachev, R. V.
六角硼硝化物是迄今为止唯一允许具有微米尺寸弹道传输的石墨烯设备的底物。可以将其他原子平坦的晶体用作制造优质石墨烯异质结构的底物吗？在这里，我们报告了搜索替代基板的搜索。发现通过将石墨烯与钼或钨二硫化物和HBN封装来制造的设备，表现出约为60 000 cm（2）V-1 S（-1）的始终高载体迁移率。相反，与原子平坦的氧化物（如云母，二氧化钙铜氧化物和五氧化钒）的封装导致具有类似于1000 cm（2）V-1 S（-1）的迁移率的石墨烯设备质量异常低。我们将差异归因于主要清洁，该自我清洁发生在石墨烯，HBN和过渡金属二核苷之间的界面。表面污染聚集成大口袋，使其余的界面在原子上变得清洁。石墨烯在原子平坦的氧化物底物上不会发生清洁过程。
Hexagonal boron nitride is the only substrate that has so far allowed graphene devices exhibiting micrometer-scale ballistic transport. Can other atomically flat crystals be used as substrates for making quality graphene heterostructures? Here we report on our search for alternative substrates. The devices fabricated by encapsulating graphene with molybdenum or tungsten disulfides and hBN are found to exhibit consistently high carrier mobilities of about 60 000 cm(2) V-1 s(-1). In contrast, encapsulation with atomically flat layered oxides such as mica, bismuth strontium calcium copper oxide, and vanadium pentoxide results in exceptionally low quality of graphene devices with mobilities of similar to 1000 cm(2) V-1 s(-1). We attribute the difference mainly to self-cleansing that takes place at interfaces between graphene, hBN, and transition metal dichalcogenides. Surface contamination assembles into large pockets allowing the rest of the interface to become atomically clean. The cleansing process does not occur for graphene on atomically flat oxide substrates.