Modeling linearity and ambipolarity in GFETs on different dielectrics for communication applications

• Published in: Journal of materials science. Materials in electronics 2018-02, Vol.29 (4), p.2883-2889
• Main Authors: Sharma, Preetika, Singh, Sukhbir, Gupta, Shuchi, Kaur, Inderpreet
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Optical and Electronic Materials
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-017-8218-2

A low voltage pristine graphene FET (GFET) using density functional theory and local density approximation (LDA) has been simulated on different dielectric regions i.e. k = 3.9, 5.0, 9.7 and 25. An enhanced device linearity and ambipolarity in its characteristics was achieved w.r.t. high k dielectric region in a GFET. The high k value of the dielectric region originated due to high capacitance yielded high linearity at low voltage operation below 2 V. The linear region obtained at k = 25 is reported to be highest (0–1.75 V) as compared to the lower dielectric values. Further, the ambipolar characteristics obtained showed most symmetrical characteristics giving similar mobility of 52 and 78 cm 2 /Vs respectively at a fixed drain bias of 1 V. Moreover, the GFET on highest k value of dielectric region exhibited highest on off ratio as compared to other lower values chosen. This observation provides a route to band gap engineering in graphene devices. Thus, for the same physical dimensions of GFET, the improvement in the device linearity and achieving symmetrical ambipolarity with the enhancement in current density at low voltages can be suggested by the use of high k dielectric region. This understanding of impact of dielectrics has great potential for future performance improvements in nanoelectronic device circuits such as amplifiers and mixers.