Multimode excitation of a metal organics frameworks coated microbeam for smart gas sensing and actuation

Abstract

Highlights The purpose of this study to demonstrate a smart sensor that is capable of performing simultaneous sensing and actuation using a single device which reduce the device size, power requirement, and cost. The concept is based on tracking the frequency shift due to external physical stimuli in the first and third modes of vibration of an electrostatically actuated clamped-clamped microbeam. The microbeam is uniformly functionalized with metal organic frameworks (MOFs) to enhance the sensitivity and selectivity of the proposed sensor. Optimizing the resonator design to excite higher order modes will open the door for simultaneously measuring multiple physical stimuli using a single resonator, which leads to smarter generation of sensors. ABSTRACTSmart sensing systems suffer complexity requiring interface circuits, microcontrollers, switches, and actuators to detect and sense, process the signal and take a decision, and trigger an action upon demand. This increases the device footprint and boosts significantly the power required to actuate the system. Here, we present a hybrid sensor and switch device, which is capable of accurately measuring gas concentration and perform switching when the concentration exceeds specific (safe)

A Resonant Gas Sensor Based on Multimode Excitation of a Buckled Microbeam

“…Furthermore, the sensitivity of the proposed device to temperature variation from the environment is an imperative factor that needs to be accounted for. The proposed technique does not simultaneously compensate the environmental temperature variation as demonstrated in some proposed gas sensors in the literature [4]. Calibration experiments, for instance, can be conducted to overcome the variation of ambient temperature.…”

“…Hence, there is a strong demand for a more sensitive probe to measure the gas concentration. Monitoring the frequency shifts of MEMS resonators due to gas concentration changes has been demonstrated as an ultra-sensitive detection technique of gases up to the molecule levels [4,18,20,21,31]. Moreover, several dynamical features, such as the bifurcation points, internal resonance, and secondary resonances have been utilized to improve the sensor sensitivity.…”

Parallel Logics Using Multimode Excitation of a Single MEMS Resonator

“…Recently, exploiting information from the different modes of vibration of a single MEMS resonator has gained significant attention in wide range of applications, such as the simultaneous measurements of temperature and humidity using two modes [16], extracting the mechanical properties and mass of adsorbed particles [17], determining the position and mass of adsorbed analytes [18,19], and demonstrating a smart sensor that can autonomously activate a switch upon exceeding a threshold value [20].…”

A Sensitive Resonant Gas Sensor Based on Multimode Excitation of a Buckled Beam

“…The quest for ultra-sensitive low-cost miniaturized gas sensors in the past few decades has sparked interest to seek alternative techniques other than the conventional gas sensors which require large surface areas and special coating materials for selective and sensitive detection. Functionalization is realized by coating the surface of the MEMS gas sensor with a thin layer of material that have affinity for particular gases, such as gold for mercury detection [1], polymer doped with carbon nanotube to detect Carbon dioxide [2], palladium for Hydrogen sensing [3], and metal-organic frameworks for humidity and volatile organic compounds [4,5]. The performance of such devices depends on the functionalization type, thickness, and the sensor design.…”

“…Monitoring the frequency of MEMS resonators due to gas concentration change has demonstrated ultra-sensitive detection of gas up to the molecule levels. Recently, significant attention has been dedicated to track the resonance frequency of MEMS resonators for gas sensing application [1,[3][4][5]10] instead of resistance variation showing higher sensitivities. Moreover, several dynamical features, such as the bifurcation points, internal resonance, and secondary resonances are utilized to improve the sensor sensitivity.…”