Abstract
Optical reflection microscopy is one of the main imaging tools to visualize graphene microstructures. Here is reported a novel method that employs refractive index optimization in an optical reflection microscope, which greatly improves the visibility of graphene flakes. To this end, an immersion liquid with a refractive index that is close to that of the glass support is used in-between the microscope lens and the support improving the contrast and resolution of the sample image. Results show that the contrast of single and few layer graphene crystals and structures can be enhanced by a factor of 4 compared to values commonly achieved with transparent substrates using optical reflection microscopy lacking refractive index optimization.
Highlights
Graphene is a novel material that has been attracting widespread interest due to its unique electronic, optical, magnetic, and mechanical properties [1,2,3,4]
Is reported a novel method that employs refractive index optimization in an optical reflection microscope, which greatly improves the visibility of graphene flakes
Results show that the contrast of single and few layer graphene crystals and structures can be enhanced by a factor of 4 compared to values commonly achieved with transparent substrates using optical reflection microscopy lacking refractive index optimization
Summary
Graphene is a novel material that has been attracting widespread interest due to its unique electronic, optical, magnetic, and mechanical properties [1,2,3,4]. For example even though only 4% of the incident light is typically reflected from a glass substrate in the visible, the optical conductivity of a single layer of graphene is such that a contrast of only 7% is obtained in the visible [33], which makes the observation of graphene on transparent substrates notoriously difficult To overcome this obstacle, a novel technique is presented here to enhance the visibility of graphene monolayers using optical reflection microscopy; by introducing a medium with a refractive index tuned sufficiently close to that of the substrate, the optical contrast of graphene flakes can be greatly enhanced. Even higher contrast values are achievable in principle by further optimization of the refractive index, accompanied by a lowering of the intrinsic noise of the detection system
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
