Potential contributors to sensor functionalities were elucidated through impedance study which is an AC measurement technique that can define contributions from grain, grain boundary, electrodes, and other associated elements. The simplicity and reproducibility of the method suggested its potential applications in the large-scale synthesis of Pd-sensitized ZnO nanorods for use in hydrogen, chemical, and other gas sensing devices that involved Pd-mediated catalysis. Methods ZnO nanorods were synthesized on silicon selleck products dioxide substrate as described in our previous research [24]. Briefly, zinc acetate dihydrate (98%;

Sigma-Aldrich Corporation, St. Louis, MO, USA) was mixed in 2-methoxyethanol (99.8%; Sigma-Aldrich) where the molarity of Zn was maintained at 0.2 M. After 30 min of stirring at room temperature, the hot plate temperature was ramped up to 60°C. Monoethanolamine (MEA) (99%; Merck & Co., Inc., Whitehouse Station, NJ, USA) was added dropwise as a stabilizer under constant stirring. The molar

ratio of MEA/Zn was maintained at 1:1. The stirring was continued until the solution turned into transparent from its PD173074 chemical structure initial whitish appearance. The prepared solution was aged for 24 h. The process flow for the device fabrication Selleck Talazoparib is depicted in Figure 1. Figure 1 Process flow for the fabrication of ZnO nanorods device. An oxide layer of approximately 1-μm thickness Bcl-w was grown on a p-type silicon substrate of resistivity 1 to 50 Ω cm through a wet oxidation process. Prior to the oxide growth, the wafer was cleaned with RCA1 and RCA2 solutions followed by draining in dilute HF to remove the native oxide. An interdigitated electrode layer was deposited onto the oxide layer through Cr/Au evaporation using a hard mask and Auto 306 thermal evaporator (Edwards High Vacuum International, Wilmington, MA, USA). ZnO seed layer was deposited on the thermally oxidized silicon substrate using a spin coater rotating at 1,000 rpm for 10 s and then ramped up to 3,000 rpm for 45 s. After coating the seed layer, the film was dried at 250°C for 20 min. The coating and drying processes were repeated five times.

After depositing five successive layers, the sample was incubated in a furnace to anneal the thin film at 450°C for 1 h under air atmosphere. For the growth of ZnO nanorods, the prepared substrate was inserted inside a Teflon sample holder at the cut edges to keep the deposited side downward inside the growth solution. The growth solution was prepared by mixing zinc nitrate hexahydrate (99%; Sigma-Aldrich) and hexamethyltetramine (99%; Merck) in deionized (DI) water, and the final concentration of the solution was maintained at 25 mM. The beaker was placed inside a preheated oven, and the growth process was continued at 90°C for 6 h. The prepared ZnO nanorods were washed in IPA and DI water to remove the excess and contaminated salts.