School of Physics, CRANN and AMBER, Trinity College Dublin, Dublin 2, Ireland.
Nanoscale. 2017 Jun 29;9(25):8657-8664. doi: 10.1039/c7nr03446f.
Graphene is a promising candidate to succeed silicon based devices, and the conventional strategies for fabrication and testing of graphene-based electronics often utilise an electron beam. Here, we report on a systematic study of the effect of electron beam exposure on graphene devices. We realise reversible doping of on-chip graphene using a focused electron beam. Our results demonstrate site-specific control of carrier type and concentration achievable by modulating the charge distribution in the substrate. The effect of substrate-embedded charges on carrier mobility and conductivity of graphene is studied, with a dielectric screening model proposed to explain the effective n-type and p-type doping produced at different beam energies. Multiple logic operations are thus implemented in a single graphene sheet by using site-specific e-beam irradiation. We extend the phenomenon to MoS, generalising it to conductive two-dimensional materials. Our results are of importance to imaging, in situ characterisation and lithographic techniques employed to investigate 2D materials.
石墨烯是一种有望替代硅基器件的材料，而传统的石墨烯基电子器件的制造和测试策略通常使用电子束。在这里，我们报告了一项关于电子束辐照对石墨烯器件影响的系统研究。我们利用聚焦电子束实现了片上石墨烯的可逆掺杂。我们的结果表明，可以通过调节衬底中的电荷分布来实现对载流子类型和浓度的特定位置控制。研究了衬底嵌入电荷对石墨烯载流子迁移率和电导率的影响，并提出了一种介电屏蔽模型来解释在不同电子束能量下产生的有效 n 型和 p 型掺杂。通过使用特定位置的电子束辐照，在单个石墨烯片上实现了多种逻辑运算。我们将这一现象扩展到 MoS2，将其推广到了导电二维材料。我们的研究结果对于用于研究二维材料的成像、原位表征和光刻技术具有重要意义。
