Charge Neutrality Point Analysis of Flexible Electrolyte Gated Gr-FET Under Bending Deformation

Electrolyte gated graphene field effect transistor (Gr-FET) -based sensors are getting popular due to their high sensitivity, low noise, electrical stability, low limit of detection, etc. As the need for flexible and wearable biosensors is on the rise, the fabrication of Gr-FET on a flexible substrate would provide a personalized biosensing platform for various sensing applications. In this direction, flexible Gr-FET must be tested against mechanical deformation to characterize the sensor and quantify the limit up to which the sensor can withstand mechanical stress or strain. A Gr-FET can be used as a sensor by tracking its Venp (gate voltage at charge neutrality point) upon variation in analyte concentrations. The fabricated electrolyte gated Gr-FET shows <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$V_{C N P}$</tex> at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1 4 0 ~ m V}$</tex> and a transconductance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left(g_{m}\right)$</tex> value with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left\vert g_{m, h o l e}\right\vert$</tex> up to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 350 \mu ~\mathrm{S}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\left\vert g_{\text {melectron }}\right\vert$</tex> up to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$300 \mu ~\mathrm{S}$</tex>. The transfer characteristics of the Gr-FET are recorded with bending deformation of different radii of curvature (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{R}$</tex>). The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{G r}$</tex>-FET shows a stable <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{V}_{\text {CNP }}$</tex> up to R= 7 cm (shift in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$V_{C N P}&lt;8 \%$</tex>).