A bottom-gate silicon nanowire field-effect transistor with functionalized palladium nanoparticles for hydrogen gas sensors

• We demonstrate the bottom-gate SiNW FET-based H2 sensor with Pd nanoparticles.
• The electrostatic properties of the sensor are enhanced due to the coupling effect.
• The enhanced electrostatic properties provide highly sensitive detection of H2.

The highly sensitive operation of a bottom-gate silicon nanowire (SiNW) field-effect transistor (FET)-based hydrogen (H2) sensor is demonstrated by controlling the working regime of the sensor. It is observed that the deposition of palladium (Pd) nanoparticles on the SiNW surface for the selective absorption of H2 can result in a significant enhancement of the electrostatic properties, such as the subthreshold swing and on-current, of the SiNW FET-based H2 sensor. By comparing the experimental results with the numerical simulation, we conclude that the improvement of the electrostatic properties of the sensor is due to the coupling effect between the electrostatic potentials in the Pd nanoparticle and bottom gate. Based on these results, highly sensitive detection of H2 gas could be achieved in the subthreshold regime where the gating effect induced by absorbed H2 gas is the most effective.