Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014)
    Nanomaterials Wednesday Sessions
       Session NM-WeP

Paper NM-WeP21
Photodetector and Pressure Sensor Based on Field-Effect Transistor with the Nanohybrid Channel of ZnO Nanorods and Graphene

Wednesday, December 10, 2014, 4:00 pm, Room Mauka

Session: Nanomaterials Poster Session
Presenter: Dang Vinh Quang, Sungkyunkwan University, Korea
Authors: D.V. Quang, Sungkyunkwan University, Korea
T.Q. Trung, Sungkyunkwan University, Korea
D.-I. Kim, Sungkyunkwan University, Korea
L.T. Duy, Sungkyunkwan University, Korea
B.-Y. Kim, Sungkyunkwan University, Korea
B.-U. Hwang, Sungkyunkwan University, Korea
D.-W. Lee, Sungkyunkwan University, Korea
N.-E. Lee, Sungkyunkwan University, Korea
Correspondent: Click to Email
Field-effect transistors (FETs) with a nano-hybrid channel of chemical-vapor-deposited graphene (CVD Gr) and vertically aligned ZnO nanostructures are successfully fabricated and operated at low volatge. By the combination of highly conductive Gr and the high UV absorption of ZnO, ultraviolet (UV) photodetectors are investigated under illumination at various incident photon intensities and wavelengths. The change in the transfer characteristics of hybrid-channel FETs under UV light illumination allows to detect both photovoltage and photocurrent. The shift of the Dirac point (VDirac) observed during UV exposure led to a clearer explanation of the response mechanism and carrier transport properties of Gr, and this phenomenon permits the calculation of electron concentration per UV power density transferred from ZnO nanorods (NRs) and ZnO nanoparticles (NPs) to Gr, which is 9 × 1010 and 4 × 1010 per mW, respectively. The time-dependent behaviours of hybrid-channel FETs exhibit high UV responsivity (RI) and high photoconductive gain (G). The maximum values of RI and G infer from the fitted curves of RI and G versus UV intensity are 3 × 105 A W-1 and 106, respectively. More interestingly, due to the piezoelectric property of ZnO, a piezoelectric-coupled hybrid channel GFET can be used as a pressure-sensing device with high responsiveness and a fast response time. The shifts of VDirac under mechanical pressurization are analysed to explain clearer the charge transferred mechanism with electron transfer of 4x108 cm-2 kPa-1 from the CVD Gr to ZnO NRs. Therefore, hybridization of semiconductor 1D nanomaterials with Gr channel in FET structures resulting in high performance and low power consumption opens up new opportunities for future optoelectronic devices.

Suggested topic: Nanomaterials (NM1-Nano Devices)