NUS Enterprise

Method of Growing Uniform, Large Scale, Multilayer Graphene Film

Technology #11371n

Few-Layers Graphene Fabrication Technique with Good Uniformity for Large Scale Production   

Prof. Loh Kian Ping, Dr. Zhang Kai, Prof. Antonio Helio Castro Neto

Department of Chemistry

Department of Physics

Industry Problem

Graphene is attractive for a wide range of applications such as high frequency transistors, flexible electronics and conducting and transparent electrodes. Growth of graphene by chemical vapor deposition on Cu foils has emerged as a powerful technique owing to its compatibility with industrial-scale roll-to-roll technology. However, challenges remain as the graphene films produced are monolayers with poor electronic mobility and conductivity (10X smaller than pristine graphene) due to grain boundaries and defects. One solution to overcome the  limitations of poor mobility and conductivity is to grow films of high quality few-layers graphene. However, as far as we know of, conventional processes yield multi-layer graphene films with poor uniformity, low conductivity and low transmittance .

Solution

Prof. Loh Kian Ping’s group from the Department of Chemistry has developed a technique to fabricate few-layers, high quality graphene films with good uniformity. Few-layer graphene films fabricated by the proposed method demonstrates good uniformity and continuity over a large area (Figs. 1 & 2), as evidenced by the uniformity of the optical contrast under the optical microscope (Fig. 2). Thickness measurement of the fabricated few-layer graphene by atomic force microscopy (AFM) shows a step height of 4.2nm, corresponding to ~10 layer graphene (Fig. 3). Figure 4 shows a Raman spectra of the graphene films synthesized by the present method as compared to multilayer graphene fabricated by conventional atmospheric pressure chemical vapor deposition (APCVD) and monolayer graphene by low pressure chemical vapor deposition (LPCVD). The lower intensity D band for few-layer graphene film synthesized by the present method suggests a higher quality film with a lower number of defects as compared to APCVD. In addition, the few-layer graphene films synthesized by the present method show lower sheet resistance (200 Ω/) as compared to conventional APCVD (500 Ω/)  and monolayer graphene by LPCVD (> 700 Ω/) and good optical transmittance (86.7% at the wavelength of 550 nm).

Keywords: Multi-layer, graphene, fabrication, uniform, large scale

Fig. 1: Photographic image of a few-layer graphene film transferred onto a Si/SiO2 substrate 

Fig. 2: Optical image of a few-layer graphene film transferred onto a Si/SiO2 substrate shows good uniformity and continuity. 

Fig. 3: Thickness measurement of a few-layer graphene film by atomic force microscopy (AFM) shows a step height of 4.2nm, corresponding to ~10 layer graphene. 

Fig. 4: Raman spectra of the graphene films synthesized by the present method as compared to conventional APCVD and monolayer graphene by LPCVD. The lower intensity D band for few-layer graphene film synthesized by the present method suggests a higher quality film with a lower number of defects as compared to APCVD. 

Fig. 5: The graphene films synthesized by the present method show lower sheet resistance (200 Ω/) as compared to conventional APCVD (500 Ω/)  and monolayer graphene by LPCVD (> 700 Ω/).

Value Proposition

  • Technique for fabrication of few-layer graphene with good uniformity, high quality, low sheet resistance and  good transmittance.
  • Few-layer graphene fabrication technique is compatible with batch processing.
  • Fabricated few-layer graphene film shows better conductivity (> 2X) and higher quality compared to films fabricated by conventional APCVD and monolayer graphene by LPCVD.

Other Potential Application

  • Semiconductor production
  • Flexible electronics
  • Sensors

For more information contact: NUS Industry Liason Office

+65 6516 7175/+65 6601 2812

iloquery@nus.edu.sg/tan.yan.ny@nus.edu.sg

Ref : 11371N

Principal Investigator: Prof Loh Kian Ping

Acknowledgement: This research is supported by the National Research Foundation, Prime Minister’s Office, Singapore under its Competitive Research Program (CRP Award No. NRF-CRP 6-2010-5 (NUS grant number R-144-000-295-281)).