**2. Significance of micro and nano fabrication in novel devices and technologies**

Micro and nano fabrication is an essential process in the manufacturing of novel devices and technologies. Many sciences, technology and engineering oriented products are developed using the concept of micro and nano fabrication. From radio transistors, integrated circuits, personal computers, to micromechanical systems (MEMS), transducers, sensors, batteries and super capacitors, solar cells, water treatment membranes and filters and other novel devices, micro and nano techniques have played significant and important role in realizing reliable technology. However, huge credit relating to the success of these technologies must be ascribed to the materials development and analyses techniques such as the analytical, macroscopic, microscopy and spectroscopy ones.

For instance, before one can realize product of gas sensor, chemical sensor and biosensor device, especially in the case of metal oxide semiconductors, carbon materials and polymers, critical studies and analyses of the materials properties is required to qualify the performance of the sensing element. The first set of investigation which must be performed on the materials intended to build these devices are crystal structure and microstructures, morphological and surface roughness studies, defects studies, thermal stability and adsorption property [8–10]. Hence, the material must be thoroughly characterized with X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) methods to study its crystal structure. X-ray diffraction spectroscopy which is commonly used technique for characterization of crystalline materials provides information about elemental analyses such as structures, phases and preferred crystal orientations. Physical measurements like average particle size of material, homogeneous and inhomogeneous strain and crystal defect could also be estimated from the data collected using XRD technique [8–11]. The HRTEM approach has been severally employed in sensors material research to unveil material's crystallographic structures at an atomic scale [8–9]. The scanning electron microscope (SEM), scanning tunneling microscope (STM) and atomic force microscope (AFM) are important for all surface structure studies such as morphology, particles distribution, nanoscale topography and

**165**

**applications**

*Micro Nano Manufacturing Methods for Chemical, Gas and Bio Sensors, Water Purification…*

surface roughness [9–13]. These are also essential properties needed to be analyzed for chemical, gas and bio sensors devices fabrication. Other properties necessary to be investigated for these types of application include quantitative analysis of the material's elemental composition and chemical state. This study is often achieved using X-ray photoelectron spectroscopy (XPS) [9–11]. The adsorption ability and properties of the sensors materials are usually evaluated using the popular Brunauer–Emmett–Teller (BET) technique which relies on the physical adsorption (physisorption) of gas molecules on the surface of solid-state materials. With this technique, information about the specific surface area, microporous, nanoporous

In the same way, materials for fabricating water and medical membranes and energy devices such as solar cell, lithium and sodium ion batteries also required critical studies with the above materials characterization techniques before the manufacturing process could be initialized. The properties which Materials Scientist and Engineers are usually sough for when building in solar cell architecture are crystal and microstructures of all the semiconductors and polymers involved. These techniques are necessary to unveiled the effect of the grain's boundaries on the charge transfer of the cell, especially when device is of a p-n junction or multi-junction type [17]. This often help materials engineers in proper understanding of interfacial properties of the cell [18]. Studies of morphology, surface roughness and topology is also of a great importance when evaluating the solar cell materials for prototyping and manufacturing. This is needed to ensure a homogeneous film surface in a bid to enhance the transport of the charges for an improve energy conversion efficiency (ECE) [19]. Thermal stability studies with Thermogravimetric analysis (TGA) are another important method adopted by materials scientist to study the degradation of solar cell device [8, 20]. Lithium and sodium ion batteries are not an exception when it comes to their materials development and analyses. TGA techniques are often used to study the thermal stability, XRD and HRTEM for crystal, micro structures, particles size analysis and how monodisperse the particle are before fabricating the device. The SEM, STM and AFM techniques are being employed for

and mesoporous of a sensor's material can be acquired [9, 14–16].

particles morphology, surface roughness and topography [21].

XPS is another important technique for qualifying materials for lithium and sodium ion battery application. XPS is suitable to give important information about the interaction of membrane-based materials with electrolyte materials and further assist to develop a definite insight of interfacial structure and as well performance of the battery. From one of the previous published studies XPS was employed and useful information of the membrane interaction with vanadium electrolytes was revealed which led to understanding of interfacial structure and battery performance [22]. Nanosized fibers have great advantages owing to their high specific surface area to volume ratio, electrospun nanofibers have find their useful applications in the field of clean energy (solar cells, fuel cells and batteries), electronics, health (biomedical scaffolds, artificial organs), and environment (filter membranes) [23].

**3. Advance manufacturing methods for chemical, gas and bio sensor** 

Prototyping and manufacturing sensor devices (Gas, Chemical or Bio sensor) required that the sensors materials be deposited or coated on an electrode for easy contact and connection to the device electronic circuitry or source measuring unit of the gas sensing and test station. Interdigitated electrode (IDE) type have been widely used for sensors laboratory research, prototyping and manufacturing of sensors and related products. This is a cost-effective method which often made from an

*DOI: http://dx.doi.org/10.5772/intechopen.94962*

#### *Micro Nano Manufacturing Methods for Chemical, Gas and Bio Sensors, Water Purification… DOI: http://dx.doi.org/10.5772/intechopen.94962*

surface roughness [9–13]. These are also essential properties needed to be analyzed for chemical, gas and bio sensors devices fabrication. Other properties necessary to be investigated for these types of application include quantitative analysis of the material's elemental composition and chemical state. This study is often achieved using X-ray photoelectron spectroscopy (XPS) [9–11]. The adsorption ability and properties of the sensors materials are usually evaluated using the popular Brunauer–Emmett–Teller (BET) technique which relies on the physical adsorption (physisorption) of gas molecules on the surface of solid-state materials. With this technique, information about the specific surface area, microporous, nanoporous and mesoporous of a sensor's material can be acquired [9, 14–16].

In the same way, materials for fabricating water and medical membranes and energy devices such as solar cell, lithium and sodium ion batteries also required critical studies with the above materials characterization techniques before the manufacturing process could be initialized. The properties which Materials Scientist and Engineers are usually sough for when building in solar cell architecture are crystal and microstructures of all the semiconductors and polymers involved. These techniques are necessary to unveiled the effect of the grain's boundaries on the charge transfer of the cell, especially when device is of a p-n junction or multi-junction type [17]. This often help materials engineers in proper understanding of interfacial properties of the cell [18]. Studies of morphology, surface roughness and topology is also of a great importance when evaluating the solar cell materials for prototyping and manufacturing. This is needed to ensure a homogeneous film surface in a bid to enhance the transport of the charges for an improve energy conversion efficiency (ECE) [19]. Thermal stability studies with Thermogravimetric analysis (TGA) are another important method adopted by materials scientist to study the degradation of solar cell device [8, 20]. Lithium and sodium ion batteries are not an exception when it comes to their materials development and analyses. TGA techniques are often used to study the thermal stability, XRD and HRTEM for crystal, micro structures, particles size analysis and how monodisperse the particle are before fabricating the device. The SEM, STM and AFM techniques are being employed for particles morphology, surface roughness and topography [21].

XPS is another important technique for qualifying materials for lithium and sodium ion battery application. XPS is suitable to give important information about the interaction of membrane-based materials with electrolyte materials and further assist to develop a definite insight of interfacial structure and as well performance of the battery. From one of the previous published studies XPS was employed and useful information of the membrane interaction with vanadium electrolytes was revealed which led to understanding of interfacial structure and battery performance [22]. Nanosized fibers have great advantages owing to their high specific surface area to volume ratio, electrospun nanofibers have find their useful applications in the field of clean energy (solar cells, fuel cells and batteries), electronics, health (biomedical scaffolds, artificial organs), and environment (filter membranes) [23].
