Sensitivity of the Micro Electro Mechanical System (MEMS) device ZnO nanosheets sensor and the Au doped ZnO nanosheets sensor has been investigated. The ZnO samples have been prepared using Hydrothermal synthesis at 90 °C. The prepared ZnO nanostructure is tested for structural morphology and crystallinity properties. The elemental analysis of the ZnO sample and Au–ZnO samples are tested by using Energy Dispersive X-ray Spectroscopy (EDS) spectrum analysis. MEMS device microheater is designed and prepared for testing the sensitivity of Ethanol gas. Thermal properties of the MEMS microheater is studied for better gas testing at different temperatures. Both the ZnO nanosheets sensor and Au doped ZnO nanosheets sensor are tested using Ethanol gas, and the gas concentrations are taken to be 15, 30, 45, and 60 ppm at 300 °C. The gas sensing response of pure ZnO nanosheets tested for ethanol gas at 60 ppm showed 20%, while the Au–ZnO nanosheets showed 35%, which is increased by 15% at similar operating conditions.

The properties of H₂S gas sensing were investigated using a ZnO nanostructure prepared with AZO (zinc oxide with aluminium) and Al surfaces which were developed on a MEMS (Micro Electromechanical System) device. Hydrothermal synthesis was implemented for the deposition of the ZnO nanostructure. To find the optimal conditions for H₂S gas sensing, different ZnO growth times and different temperatures were considered and tested, and the results were analysed. At 250 °C and 90 min growth time, a ZnO sensor prepared with AZO and 40 nm Al recorded an 8.5% H₂S gas-sensing response at a 200 ppb gas concentration and a 14% sensing response at a gas concentration of 1000 ppb. The dominant sensing response provided the optimal conditions for the ZnO sensor, which were 250 °C temperature and 90 min growth time. Gas sensor selectivity was tested with five different gases (CO, SO₂, NO₂, NH₃ and H₂S) and the sensor showed great selectivity towards H₂S gas.

Microlens arrays (MLAs) play a prominent role and are essential components in the fabrication of 3D imaging and optical systems. Traditional MLA patterns have limited applications, which prompts the demand for novel MLA patterns for advanced applications. The fundamental objective of this study is to demonstrate different types of MLA fabrication process within our department, employing custom-developed equipment for industrial applications. The three distinctive MLA patterns that were designed and developed are symmetrical, non-symmetrical and step-layer pattern MLAs. MATLAB and Auto CAD 2D software were used to design the MLA patterns, and they were developed on a 4 inch silicon wafer using maskless exposure lithography and thermal reflow techniques. The fabricated master mold acts as a template for replicating pattern molds on a glass wafer. Photoresist ma-p-1275 G and polydimethylsiloxane resin were used for pattern development on silicon wafer and glass wafer, respectively. The fabricated MLA patterns were characterized with an optical microscope and scanning electron microscopy. The fabricated MLA pattern replicas offer durability, longevity, reusability and scalability for large-scale productions. The current study offers a comprehensive approach to in-house production on different types of MLA pattern fabrications.