Nitrided and Fluorinated Graphene for the Applications on High Mobility Graphene Transistor, Memory and Chemical Sensors

The University Lecture on “Nitrided and Fluorinated Graphene for the Applications on High Mobility Graphene Transistor, Memory and Chemical Sensors” will take place as follows:

Date: 24 July 2019 (Wednesday)

Time: 11:00am - 12:30pm

Venue: N21-G013, Lecture Hall, Research Building, University of Macau


The speaker is:

Prof. Chao-Sung LAI, Professor, Dean of Engineering College of Chang Gung University


The Lecture is:

Nitrided and Fluorinated Graphene for the Applications on High Mobility Graphene Transistor, Memory and Chemical Sensors



A novel graphene based insulator, fluorographene, is firstly applied as gate dielectric in a field effect transistor. To identify the dielectric quality, dielectric constant, breakdown electric field and thermal stability are investigated. In this talk, the scalable and one-step fabrication of single atomic-layer transistors is demonstrated by the selective fluorination of graphene using a low-damage CF4 plasma treatment, where the generated F-radicals preferentially fluorinated the graphene at low temperature (<200 °C) while defect formation was suppressed by screening out the effect of ion damage. The fluorographe was also used as decoupling for graphene as its substrate and mobility was improved much. Graphene nanodiscs (GNDs), functionalized using NH3 plasma, as charge trapping sites (CTSs) for non-volatile memory applications have been investigated. The fabrication process relies on the patterning of Au nanoparticles (Au-NPs), whose thicknesses are tuned to adjust the GND density and size upon etching. A GND density as high as 8 × 10¹¹ cm⁻² and a diameter of approximately 20 nm are achieved. The functionalization of GNDs by NH3 plasma creates NH⁺ functional groups that act as CTSs, as observed by Raman and Fourier transform infrared spectroscopy. This inherently enhances the density of CTSs in the GNDs, as a result, the charge loss is less than 10% for a 10-year data retention testing, making this low-temperature process suitable for low-cost non-volatile memory applications on flexible substrates. Moreover, the pH, pNa ion sensing properties of graphene based ion-sensor by nickel end contact modification were demonstrated. The pH and pNa sensitivities were around 36.5mV/pH and 15.3mV/pNa, respectively, for pristine graphene. For Ni end-contact modified graphene, sensitivities are changed to 41mV/pH and no pNa sensitivity.



Chao-Sung Lai received the B. S. and ph. D. degrees from National Chiao Tung University, Hsinchu, Taiwan, in 1991 and 1996, respectively. In 1996, he joined National Nano Device Laboratories, Hsinchu, where was engaged in the research of silicon-on-insulator devices. He then, in 1997, joined Chang Gung University as a faculty in the department of electronic engineering. He has been engaged in the research of the characterization and reliability of MOSFETs, Flash memory and transistor based biosensors. From 2001 to 2002, he visited the Department of Electrical Engineering, University of California, Berkeley, for visiting research on fin-shaped FETs. Since 2007 to 2013, he had been the Chairman of the Department of Electronic Engineering and the Director of the Biosensor Group of the Biomedical Research Center, Chang Gung University, for the research-related bio-transistor application on ions, proteins, DNA, and biomarker analysis. From 2012 till now, he is the Dean of Engineering College of Chang Gung University. He holds 11 U.S. patents and 60 Taiwan patents, and he is the author of more than 350 SCI journal and conference papers, 25 international invited talks, and 2 book chapters. He is the Leading Guest Editor of the SCI journals, including Microelectronics Reliability (2010), Nano-Scaled Research Letters (2011), and Solid-State Electronics (2012). He won Lam Research Award in 1997 and distinguished award from Electron Devices and Materials Association in 2011 and Association of Chemical Sensing Technology in 2015. From 2016, he was elected as the president of Association of Chemical Sensing Technology. He has served as organizing committees for several international conferences, including general chair (IEEE-INEC 2011), (IEEE-ISNE 2015) and international advisory committee (IEEE-ISNE 2016) and (IEEE-EDSSC 2017).


For more details, kindly find the event poster, abstract and bio.