Graphene Sensing Modulator: Toward Low-Noise, Self-Powered Wireless Microsensors

Machine Learning Assisted Multi-Functional Graphene-Based Harmonic Sensors

“…Figure 2(a) illustrates the working principle of higher harmonics generation based on the combination of two ideal GFETs by different charge natural points (Vcnp), where the fundamental frequency implied at the common gate of both GFET is generating higher harmonics at the drain output; here with tuning the Vcnp of each GFET, the drain current-gate voltage characteristic at the circuit output can be reshaped to a "W" shape viable to generate higher harmonics of frequency. Hence, we can expand the recent GFET based harmonic sensor system performance [11], [18] to the new paradigm of multi-agent sensing application using the same physics-based drift-diffusion model for analytical study (see Appendix) which has been quite matched with our recent experimental report [18]. Here a compact physics-based GFET model is employed to numerically study the multi-GFET harmonic sensor system, in which the model characterization is practically verified with the experimental measurement of the fabricated GFET that is detailed in our prior study on reference [18].…”

“…Hence, we can expand the recent GFET based harmonic sensor system performance [11], [18] to the new paradigm of multi-agent sensing application using the same physics-based drift-diffusion model for analytical study (see Appendix) which has been quite matched with our recent experimental report [18]. Here a compact physics-based GFET model is employed to numerically study the multi-GFET harmonic sensor system, in which the model characterization is practically verified with the experimental measurement of the fabricated GFET that is detailed in our prior study on reference [18]. The new circuit design of nonidentical GFETs not only shows a unique behavior that benefits higher harmonics generation but also functionalizing graphene surface develops the sensor's selectivity area to a wider range of chemical or biological agents.…”

“…Figure 3 shows the simulation results for the unified circuit I-V curve and the corresponding output of fifth first frequency harmonics amplitude for the three boundary conditions as the balanced (a), n-type agent binding (agent1) (b), and p-type agent binding (agent2) (c) effects. The Vcnp variation scale is inspired from our previous measurement for a PH sensor based on the single GFET [18], where the PH value of buffer solution drop-casted onto the graphene channel results in a voltage deviation around 2 V for a range of pH 7 to 3 values. Hence we assume that each agent at a maximum binding level can shift the absolute value of Vcnp for 2 V. Consider the GFETs biased at a certain DC drain voltage, an RF input signal (a monochromatic, sinusoidal wave) can be efficiently converted to its higher harmonics.…”

Graphene nanoelectromagnetics: From radio frequency, terahertz to mid-infrared

“…Photopumped optical gain in graphene have been theoretically and experimentally studied by Rana [15], Rhyzii and Otsuji et al [44]- [48], and recently detailed by Garcia-Vidal and Hess et al [49] [45], who have conducted more rigorous calculations considering realistic conditions (e.g., collision losses and temperature profiles). Under this non-equilibrium condition, graphene's THz properties become particularly interesting because the population inversion and thus negative dynamic conductivity (which implies a THz gain) can take place in a photopumped graphene, as a result of the cascaded optical-phonon emission and interband transitions around the Dirac point [45]- [48], as illustrated in Fig.…”

“…The high carrier mobility and ambipolar charge transports in graphene make the graphene-based transistors a compelling platform for radio-frequency (RF) and analog electronics. The symmetric "Vshape" drain current-gate voltage characteristic of a graphene field-effect transistors (GFET) can realize the simplest possible frequency multiplier, converting the input RF signal into its second harmonic [43], [44], [97]- [100]. This unique characteristic is not found in conventional semiconductor microelectronic devices.…”