title: Measuring the refractive index of highly crystalline monolayer MoS2 with high confidence.
abstract: Monolayer molybdenum disulphide (MoS2) has attracted much attention, due to its attractive properties, such as two-dimensional properties, direct bandgap, valley-selective circular dichroism, and valley Hall effect. However, some of its fundamental physical parameters, e.g. refractive index, have not been studied in detail because of measurement difficulties. In this work, we have synthesized highly crystalline monolayer MoS2 on SiO2/Si substrates via chemical vapor deposition (CVD) method and devised a method to measure their optical contrast spectra. Using these contrast spectra, we extracted the complex refractive index spectrum of monolayer MoS2 in the wavelength range of 400 nm to 750 nm. We have analyzed the pronounced difference between the obtained complex refractive index spectrum and that of bulk MoS2. The method presented here is effective for two-dimensional materials of small size. Furthermore, we have calculated the color contour plots of the contrast as a function of both SiO2 thickness and incident light wavelength for monolayer MoS2 using the obtained refractive index spectrum. These plots are useful for both fundamental study and device application.
authors: 1] State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors: Hui
authors: H
authors: Zhang
authors: State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China.
authors: Yaoguang
authors: Y
authors: Ma
authors: State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China.
authors: Yi
authors: Y
authors: Wan
authors: State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China.
authors: Xin
authors: X
authors: Rong
authors: State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China.
authors: Ziang
authors: Z
authors: Xie
authors: State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China.
authors: Wei
authors: W
authors: Wang
authors: 1] State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors: Lun
authors: L
authors: Dai