MEMS based highly sensitive dual FET gas sensor using graphene decorated Pd-Ag alloy nanoparticles for H2 detection

Abstract

A low power, dual-gate field-effect transistor (FET) hydrogen gas sensor with graphene decorated Pd-Ag for hydrogen sensing applications was developed. The FET hydrogen sensor was integrated with a graphene-Pd-Ag-gate FET (GPA-FET) as hydrogen sensor coupled with Pt-gate FET as a reference sensor on a single sensor platform. The sensing gate electrode was modified with graphene by an e-spray technique followed by Pd-Ag DC/MF sputtering. Morphological and structural properties were studied by FESEM and Raman spectroscopy. FEM simulations were performed to confirm the uniform temperature control at the sensing gate electrode. The GPA-FET showed a high sensing response to hydrogen gas at the temperature of 25~254.5 °C. The as-proposed FET H2 sensor showed the fast response time and recovery time of 16 s, 14 s, respectively at the operating temperature of 245 °C. The variation in drain current was positively related with increased working temperature and hydrogen concentration. The proposed dual-gate FET gas sensor in this study has potential applications in various fields, such as electronic noses and automobiles, owing to its low-power consumption, easy integration, good thermal stability and enhanced hydrogen sensing properties.

Fast Hydrogenation and Dehydrogenation of Pt/Pd Bimetal Decorated over Nano-Structured Ag Islands Grown on Alumina Substrates

“…In addition, the complex alloy formation may increase the response of hydrogenation permeation by increasing the active surface coverage. Furthermore, it was found that Ag alloying with Pd can be advantageous for the embrittlement and mechanical issue of Pd lattice which might be more improved with the Pt/Pd@Ag nanoislands case [76,77]. A higher surface to volume ratio-based Ag nanoislands enhances the bimetal capping configuration that makes a percolation pathway that is suitable for higher carrier mobility.…”

A Si FET-type Gas Sensor with Pulse-driven Localized Micro-heater for Low Power Consumption

“…Compared to the micro-heaters embedded in the MEMS-based gas sensors reported by the other groups [11,12,33], the micro-heater used in this work can achieve much higher temperature with the same power consumption as displayed…”

“…In addition, a large size of heater is required to raise the operating temperature due to its large sensing area, resulting in high power consumption [11,12,33]. [13].…”

“…This is because air has a very low thermal conductivity compared to other materials as displayed in Table 1.1. Table 1.2 shows a summary of the recent studies on MEMS-based gas sensors with a micro-heater reported by other research groups [11,12,33]. The sizes of all the micro-heaters shown in Table 1.2 are large so that they consume high power.…”

Microhotplates for Metal Oxide Semiconductor Gas Sensor Applications—Towards the CMOS-MEMS Monolithic Approach

“…However, metal gate materials, such as palladium and platinum, are only sensitive to hydrogen. Recently, many works have been done on the gate design to improve the performance of the FET sensors by applying nanomaterials, such as carbon nanotubes [ 16 ] and graphene [ 17 ], or by a thin charge inversion layer [ 18 ]. MOX gas sensors measure the conductance change of the metal oxide layer and play a dominant role in both research studies and commercial products because they have the most balanced overall performance and low fabrication cost.…”