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Nanoscience and Nanoengineering(CEASE PUBLICATION) Vol. 5(2), pp. 17 - 24
DOI: 10.13189/nn.2017.050201
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Effect of Nanowire-dielectric Interface on the Hysteresis of Solution Processed Silicon Nanowire FETs

K Prabha Rajeev , C Opoku, V Stolojan , M Constantinou , M Shkunov ^*
Department of Electrical and Electronic Engineering, Advanced Technology Institute, University of Surrey, United Kingdom

ABSTRACT

Silicon nanowires (Si NW) are ideal candidates for low-cost solution processed field effect transistors (FETs) due to the ability of nanowires to be dispersed in solvents, and demonstrated high charge carrier mobility. The interface between the nanowire and the dielectric plays a crucial role in the FET characteristics, and can be responsible for unwanted effects such as current hysteresis during device operation. Thus, optimal nanowire- dielectric interface is required for low-hysteresis FET performance. Here we show that NW FET hysteresis mostly depends on the nature of the dielectric material by directly comparing device characteristics of dual gate Si NW FETs with bottom SiO₂ gate dielectric and top hydrophobic fluoropolymer gate dielectric. As the transistor semiconducting nanowire channel is identical in both tops and bottom operational regimes, the performance differences originate from the nature of the nanowire-dielectric interface. Thus, very high 30 volt hysteresis is observed for forward and reverse gate bias scans with SiO₂ interface; however, hysteresis is significantly reduced to 6 volt for the fluoropolymer dielectric interface. The differences in hysteresis are ascribed to the polar OH- groups present at SiO₂/Si nanowire interface, and mostly absent at fluoropolymer/Si nanowire interface. We further demonstrate that high density of charge traps for bottom gate SiO₂ interface (1脳 10¹³cm^-2) is reduced by over an order of magnitude for top-fluoropolymer gate interface (7.5 脳 10¹¹ cm^-2), therefore highlighting the advantage of hydrophobic polymer gate dielectrics for nanowire field-effect transistor applications.

KEYWORDS
Nanowire Field-effect Transistor, Hysteresis, Silicon Nanowires, Nanowire Interface, Double Gate Transistor, Polymer Dielectric, Encapsulation

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] K Prabha Rajeev , C Opoku, V Stolojan , M Constantinou , M Shkunov , "Effect of Nanowire-dielectric Interface on the Hysteresis of Solution Processed Silicon Nanowire FETs," Nanoscience and Nanoengineering(CEASE PUBLICATION), Vol. 5, No. 2, pp. 17 - 24, 2017. DOI: 10.13189/nn.2017.050201.

(b). APA Format:
K Prabha Rajeev , C Opoku, V Stolojan , M Constantinou , M Shkunov (2017). Effect of Nanowire-dielectric Interface on the Hysteresis of Solution Processed Silicon Nanowire FETs. Nanoscience and Nanoengineering(CEASE PUBLICATION), 5(2), 17 - 24. DOI: 10.13189/nn.2017.050201.