Large‐Scale Suspended Graphene Used as a Transparent Substrate for Infrared Spectroscopy. Issue 25 (16th May 2017)

• Record Type: Journal Article
• Authors: Hu, Hai; Liao, Baoxing; Guo, Xiangdong; Hu, Debo; Qiao, Xiaofen; Liu, Ning; Liu, Ruina; Chen, Ke; Bai, Bing; Yang, Xiaoxia; Dai, Qing
• Is Part Of: Small. Volume 13:Issue 25(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-05-16
• Subjects: graphene transferring -- infrared spectroscopy -- infrared windows -- suspended graphene -- transparent substrates; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201603812
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract : Due to weak interactions between micrometer‐wavelength infrared (IR) light and nanosized samples, a high signal to noise ratio is a prerequisite in order to precisely characterize nanosized samples using IR spectroscopy. Traditional micrometer‐thick window substrates, however, have considerable IR absorption which may introduce unavoidable deformations and interruptions to IR spectra of nanoscale samples. A promising alternative is the use of a suspended graphene substrate which has ultrahigh IR transmittance (>97.5%) as well as unique mechanical properties. Here, an effective method is presented for fabrication of suspended graphene over circular holes up to 150 µm in diameter to be utilized as a transparent substrate for IR spectroscopy. It is demonstrated that the suspended graphene has little impact on the measured IR spectra, an advantage which has led to the discovery of several missing vibrational modes of a 20 nm thick PEO film measured on a traditional CaF2 substrate. This can provide a better understanding of molecules' fine structures and status of hanging bands. The unique optical properties of suspended graphene are determined to be superior to those of conventional IR window materials, giving this new substrate great potential as part of a new generation of IR transparent substrates, especially for use in examining nanoscale samples. Abstract : Large area suspended graphene (150 µm in diameter) is fabricated and utilized as a transparent substrate for IR spectroscopy. It is experimentally demonstrated to have little interference on the measured IR spectra, which displays several missing vibrational modes of the 20 nm thick PEO film when measured on a CaF2 substrate. It holds great potential for next‐generation infrared substrates for nanoscale measurement.