The voltage source is then turned on which begins the etching process. The tungsten wire is then dipped through the center of the lamella and into the KOH in the beaker. The beaker below the ring is then filled with KOH and the positive terminal of the voltage source is wired into the KOH solution. The negative terminal of the voltage source is then connected to the suspended metallic ring. A drop of KOH is added to the metal ring suspended above the beaker, forming a thin film or lamella of KOH inside the metallic ring. Among the requirements for this process are a metallic ring, a beaker, Potassium Hydroxide (KOH), tungsten wire, and a voltage source. The single lamella technique is easy to setup and can consistently produce sharp tips. There are a variety of methods to choose from to etch the tungsten wire. These sharp tungsten tips can be mounted to quartz tuning forks for AFM or for other types of scanning probe microscopy like scanning tunneling microscopy (STM). Post etching techniques can even sharpen the tip down to a <1nm tip radius. This method can produce a tip radius of better than 50nm. One way to produce sharp probe tips suitable for building an AFM is to electrochemically etch tungsten wire. Another advantage is that quartz tuning forks are quite plentiful and very inexpensive as they are manufactured by the billions annually for their primary use as time keeping devices.Īpplication Example: Tungsten Tip EtchingĪn etched tungsten tip glued to a quartz tuning fork. Quartz tuning forks also have extremely stable resonance frequencies, and lower temperature coefficients than silicon, making them less susceptible to drift. This eliminates the need for an external shaker which is necessary for silicon cantilevers working in intermittent or non contact modes. The tuning forks can also be actuated directly with an electrical signal. The smaller oscillation amplitudes makes it easier to perform various near field experiments as the tip spends most, if not all, of its oscillation cycle near the surface. The increased stiffness means that the probe will have higher force sensitivity. Tuning fork probes are also typically much stiffer and have smaller oscillation amplitudes than cantilever probes. The additional light from a laser deflection system can interfere with readings and photobleach samples, hindering the ability to take data. NSOM requires low light conditions for optimal signal to noise ratio. The use of a deflection laser can also be detrimental to some experiments. This also translates into a decrease in cost and size of the system because laser and PSD modules are not needed. The resonant probe only needs basic initial tuning a process which can be fully automated with commercially available products like the MadPLL ®. Laser alignment is not necessary which saves significant time and effort when exchanging probes. Resonant probe AFMs offers several advantages over the optical deflection methods. Bare tuning forks available in boxes of 20, tuning forks with tungsten tips available in boxes of 8. Our tuning forks are available in two sizes, and are shipped to you conveniently ready to use - "out of the can" - with the typical cylindrical housing removed. Each tuning fork has two electrical leads for connection to a driving oscillator such as the Mad City Labs MadPLL ® instant AFM and nanoprobe instrumentation. Mad City Labs offers quartz crystal tuning forks for scanning probe microscopy applications such as atomic force microscopy (AFM) and near-field scanning optical microscopy (NSOM). Near-field Scanning Optical Microscopy (NSOM).Also available with tungsten tips attached.Ready to use - no cylindrical can packaging to remove.Home Products Applications Catalog Custom/OEM Technical Information News International Sales Repairs Contact Quartz Crystal Tuning Forks | Scanning Probe Microscopy, AFM, NSOM, and Nanoprobe Accessories
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