Light-emitting diodes by band-structure engineering in van der Waals heterostructures
Light-emitting diodes by band-structure engineering in van der Waals heterostructures
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DOI：
10.1038/nmat4205
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发表时间：
2015-03-01
期刊：
影响因子：
41.2
通讯作者：
Novoselov, K. S.
中科院分区：
文献类型：
--
作者：
Withers, F.;Del Pozo-Zamudio, O.;Novoselov, K. S.
石墨烯和相关的2D材料1，2的出现最近导致了一项新技术：基于这些原子薄晶体的异质结构(3)。这种模式被证明是非常多才多艺的，并导致了具有负差分电阻的隧道二极管(4)、隧道晶体管(5)、光伏器件(6，7)等的快速演示。在这里，我们通过引入具有单原子平面精度的量子阱(QWS)，将这种范德华异质结构的复杂性和功能性带到了一个新的水平。我们描述了通过堆叠金属石墨烯、绝缘六方氮化硼和各种半导体单层制成的发光二极管(LED)，这些序列复杂但经过精心设计。我们的第一批器件已经显示出近10%的非本征量子效率，通过适当地选择和组合2D半导体(过渡金属二盐基单分子膜)，发射可以在很大的频率范围内进行调节。通过在弹性和透明衬底上制备异质结，我们表明它们也可以为柔性和半透明电子学提供基础。随着2D晶体数量的增加和电子质量的提高，所展示的异质结构的功能范围有望进一步扩大。
The advent of graphene and related 2D materials1,2 has recently led to a new technology: heterostructures based on these atomically thin crystals(3). The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance(4), tunnelling transistors(5), photovoltaic devices(6,7) and so on. Here, we take the complexity and functionality of such van der Waals heterostructures to the next level by introducing quantum wells (QWs) engineered with one atomic plane precision. We describe light-emitting diodes (LEDs) made by stacking metallic graphene, insulating hexagonal boron nitride and various semiconducting monolayers into complex but carefully designed sequences. Our first devices already exhibit an extrinsic quantum efficiency of nearly 10% and the emission can be tuned over a wide range of frequencies by appropriately choosing and combining 2D semiconductors (monolayers of transition metal dichalcogenides). By preparing the heterostructures on elastic and transparent substrates, we show that they can also provide the basis for flexible and semi-transparent electronics. The range of functionalities for the demonstrated heterostructures is expected to grow further on increasing the number of available 2D crystals and improving their electronic quality.