Hybridized Graphene Oxide FETs with Amplified Gas Sensitivity

The current study concerns a new approach to achieve amplified gas sensitivity in hybrid graphene oxide (GO) based field effect transistors (FET) sensors. Chemically synthesized TiO
2
nanoparticles, WO
3
nanoflowers and Pd nanoparticles were used to functionalize GO channel which was then implemented in back gated FET structure sensors fabricated on SiO
2
/Si substrate. Morphology of pure and hybridized GO were characterized with field emission scanning electron microscopy. IDS-VGS characteristics of all the FET sensors were measured in air and 100 ppm of ethanol/acetone ambient. Interestingly, all the sensors exhibited a peak response magnitude at a particular $\mathrm{V}_{\mathrm{G S}}$ closed to the Dirac point. Therefore, to achieve a high sensitivity, transient response was measured at $\mathrm{V}_{\mathrm{G S}} \approx \mathrm{V}_{\mathrm{Dirac}}$, while $\mathrm{V}_{\mathrm{D S}}=1 \mathrm{V}$ (constant). ~49%, ~55%, ~229% and ~129% response towards 100 ppm of ethanol/acetone were recorded for pure GO, p-TiO
2
-GO, WO
3
- GO and Pd-GO sensors, respectively. The recorded responses at $\mathrm{V}_{\mathrm{G S}} \approx \mathrm{V}_{\mathrm{{Dirac}}}$ were. 7,11,21 and 64 times amplified than that of the $\mathrm{V}_{\mathrm{G S}}=0$. The amplified sensitivity was achieved by modulating the carrier concentration of GO channel through optimized gate electrostatic. The functionalization of GO with TiO
2
, WO
3
and Pd further enhanced the catalytic activity, selectivity, dissociative adsorption properties of the sensing channel towards different VOCs.