Piranha solution

Si wafers were either cleaned in Piranha solution, washed with deionized water and dried with Ar gas, or used without cleaning. The samples were then inserted into the high temperature tube furnace. Since SAN can form extremely fast, we believe that SAN existed in all samples. When the furnace temperature was set between 1035 and 1100°C, SiNW were formed. 

Effect of SAN. We also investigated the contribution of SAN to the growth of SiNW. In these experiments, extra Co left on the substrate after the synthesis of SAN was removed from the SAN samples by washing it in Piranha solution. The Co in those washed samples was in the form of almost pure CoSi2, as verified by XAS measurements (vide infra). These cleaned samples were then used to grow SiNW at 1100°C. It was found that moderate yields of SiNW were produced. 

After the mechanical pre-treatment, the electrode can be subjected to a chemical and/or electrochemical pre-treatement. Chemical treatment consists mainly of etching of a few layers of the metal, including possible contaminants. A well-known etching solution for gold is the so-called piranha solution. Other reported solutions are kali, which is a concentrated KOH solution to remove fats and oils and etch off a layer of platinum. 

Cleaning of SPR glass slides (optical grade SF2, refractive index 1.65, from UQG Optical Components). Sonicator (e.g., Lucas Dawe sonication bath) and different solutions hydrochloric acid/nitric acid 3 1 v/v (solution A) ammonium cerium nitrate (1M) (solution B) sulfuric acid/hydrogen peroxide 1 1 (Piranha solution) isopropanol. Use caution in handling these solutions harmful and corrosive. 

SV detection was also achieved to detect catecholamines on a PDMS-quartz chip. Pyrolyzed photoresist films (PPF) were used as planar carbon electrodes. Since the photoresist (AZ4330) must adhere on a substrate for pyrolysis at 1000°C, a quartz plate that could withstand high temperature was selected. The LOD of dopamine decreased from 160 nM to 100 nM when the PPF was treated by piranha solution (HjSOyHjOj). It was because such a treatment increased the surface oxygen/carbon ratio, and hence the oxidation kinetics of dopamine wave improved [765]. 

Multilayer films were fabricated directly on one side of preliminary cleaned in a piranha solution quartz crystal resonators with gold working surface having the basic oscillation frequency of 5 MHz. The resonators were covered with a PEI/PSS layer if needed. The adsorption of PEI and PSS was carried out from 1 mg/mL polyelectrolyte solutions. Each adsorption step was followed by washing the resonator with the film in distilled water to remove an excess polyelectrolyte. 

Piranha Solution contains a mix 70 30 of sulphuric acid 96% (Merk KGaA no 100732) and hydrogen peroxide 30% (Panreac, no 121076). The solution should be prepared 5-10min before used, adding the sulfuric acid first, and followed by the peroxide. Never store piranha solutions. Piranha stored in a closed container will likely explode. Caution Piranha solution is very dangerous. It is extremely energetic and may result in explosion or skin burns if not handled with extreme caution. 

Dry carefully the cantilever under nitrogen flow and submerge it for 1 min on fresh piranha solution (70% H2SO4-30%... 

Piranha solution (7 3 volume ratio of concentrated H2S04 and 30% H202) Caution piranha solution reacts violently with many organic materials and should be handled with great care. 

Prepare the piranha solution. Dip the distal end of the sensor (glass layer) in piranha solution for 3 min. Rinse in copious amounts of DI. Dry in a dust-free oven at 80°C for 1 h. 

SAM Formation. SAMs of 11-MUA were prepared ex situ in 1-3 mM ethanolic solution of 11-mercaptoundecanoic acid, which was purchased at Sigma Aldrich. Two different substrates were used Au(lll)/mica and recrystallized gold foils. Typically, substrates are cleaned in piranha solution. This procedure was not possible for Au( 11 l)/mica, because it led to a separation of the gold layer from the mica substrate. Therefore, both substrates were cleaned in a UHV chamber by Ar+ -sputtering, followed by short annealing at 800 K to get a smooth surface. After removal from the vacuum chamber, it was immediately immersed into the solution. Typically samples remained for 48 h in the solution. After removal out of solution, the samples were rinsed with ethanol and dried with C02 - spray. 

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