High-Mobility, Wet-Transferred Graphene Grown by Chemical Vapor Deposition

We report high room-temperature mobility in single layer graphene grown by Chemical Vapor Deposition (CVD) after wet transfer on SiO$_2$ and hexagonal boron nitride (hBN) encapsulation. By removing contaminations trapped at the interfaces between single-crystal graphene and hBN, we achieve mobilities up to$\sim70000cm^2 V^{-1} s^{-1}$ at room temperature and$\sim120000cm^2 V^{-1} s^{-1}$ at 9K. These are over twice those of previous wet transferred graphene and comparable to samples prepared by dry transfer. We also investigate the combined approach of thermal annealing and encapsulation in polycrystalline graphene, achieving room temperature mobilities$\sim30000 cm^2 V^{-1} s^{-1}$. These …

Microwave gas sensor based on graphene aerogel for breath analysis

Exhaled breath can be used for early detection and diagnosis of diseases, monitoring metabolic activity, and precision medicine. In this work, we design and simulate a microwave sensor in which thin graphene aerogels are integrated into rectangular microwave waveguides. Graphene aerogels are ideal sensing platforms for gases and volatile compounds as they combine extremely high surface-to-volume ratio and good electrical conductivity at RF and microwave frequencies. The latter is modified by exposure to different gases, and -when integrated into a waveguide- these changes result in significant shifts in transmission and reflection scattering parameters. We model the aerogel as a graphene gr…

High-sensitivity narrow-band CSRR-based Microwave Sensor for Monitoring Glucose Level

In this paper, a high-sensitivity narrow-band microwave sensor based on a complementary split-ring resonator (CSRR) to detect glucose concentrations in an aqueous solution is presented. The sensor consists of three CSRR cells engraved on the bottom level of a 59 mm x 20 mm x 0.8 mm FR4 (εr=4.3) dielectric substrate with a sensing area of 36 x 20 mm2. The cells operate over the 2.3 - 2.4 GHz band and are powered by a 50 Ω microstrip waveguide at the bottom of the substrate. A sensitivity analysis, starting from an optimization of the thickness of the glass layer added to the cells to avoid short circuits between the sample solution and the CSRRs rings, is performed. The sensitivity analysis …

Dispositivi elettronici in grafene.