CAJ | 학술논문

本文以鉴别机械剥离法制备的高质量石墨烯样品的层数为例,阐明了如何利用传输矩阵来计算二维原子晶体薄片样品的光学衬度,并进一步精确地鉴别其层数.计算结果表明测试时所选用的显微物镜数值孔径对精确确定薄片样品的层数非常重要,并为实验所证实.同时提出了使用两个激光波长可以快速地表征样品尺寸接近物镜衍射极限的薄片样品层数的方法.本文所采用的传输矩阵形式非常适合于计算二维原子晶体薄片样品的光学衬度,并可以方便地推广到更复杂的多层衬底结构,以便快速和准确地鉴别各种衬底上二维原子晶体薄片样品的厚度.
본문이감별궤계박리법제비적고질량석묵희양품적층수위례,천명료여하이용전수구진래계산이유원자정체박편양품적광학츤도,병진일보정학지감별기층수.계산결과표명측시시소선용적현미물경수치공경대정학학정박편양품적층수비상중요,병위실험소증실.동시제출료사용량개격광파장가이쾌속지표정양품척촌접근물경연사겁한적박편양품층수적방법.본문소채용적전수구진형식비상괄합우계산이유원자정체박편양품적광학츤도,병가이방편지추엄도경복잡적다층츤저결구,이편쾌속화준학지감별각충츤저상이유원자정체박편양품적후도.
The optical and electronic properties of two-dimensional atomic crystals including graphene are closely dependent on their layer numbers (or thickness). It is a fundamental issue to fast and accurately identify the layer number of multilayer flakes of two-dimensional atomic crystals before further research and application in optoelectronics. In this paper, we discuss in detail the application of transfer matrix method to simulate the optical contrast of ultrathin flakes of two-dimensional atomic crystals and further to identify their thickness, where numerical aperture of microscope objective is considered. The importance of numerical aperture in the thickness determination is confirmed by the experiments on the graphene flakes. Furthermore, two lasers with different wavelengths can be serviced as light sources for the thickness identification of flakes of two-dimensional atomic crystals with a size close to the diffraction limit of the microscope objective. The transfer matrix method is found to be very useful for the optical-contrast calculation and thickness determination of flakes of two-dimensional atomic crystals on multilayer dielectric substrate.