Miscellaneous
12. March 2021Besides microscopes and optical devices, a lot of other equipment/infrastructure is required to fabricate and characterize the electro-optical nano-antennas. Here, some of it will be highlighted.
Liquid Nitrogen
The HIM consumes 15 liter liquid nitrogen (LN2) a day for cooling it down to ~55 K (-218°C) and getting the helium ionization to work. (To achieve these temperatures the LN2 is solidified via vacuum evaporation.) Additionally, we require gaseous nitrogen for many different applications.
The 1000 liter LN2 tank.
Fortunately, the RCCM was planned with the necessary piping for a centralized supply of the gaseous nitrogen to all labs and in case of the LN2 to the clean room. Therefore, we only* had to organize a LN2 tank since it also can be used as a gaseous-nitrogen source.
*This took just a year.
Wet Chemistry
The next important infrastructure point is the wet chemistry corner. For growing flakes and transferring them, cleaning fibbed structure, functionalizing antennas or many more process steps a wet chemistry area is crucial.
Our wet chemistry corner when it was new with fume hood, waste cabinet, working bench, dish washer and freezer/fridge visible.
Fortunately, a separated part of the clean room was already designated for a chemistry corner and so we just needed to equip it with a wet bench (not shown), fume hood, working bench, waste cabinet, dish washer, freezer/fridge and chemical cabinet*. Devices such as a ultrasonic bath, a plasma cleaner, a vortex shaker, lab ovens, heat plates, spin coaters, precise scales and so on were also procured.
*The latter was already built in and is also not shown.
ALD
An Atomic Layer Deposition (ALD) is capable of — as the name suggests — depositing individual layers of atoms on nearly any substrate. Wikipedia has a nice page on how it works. As each layer is complete and one can determine the thickness by simply counting the cycles, it is possible to fabricate for example very thin but still insulating films with an ALD.
The Anric Technologies AT-410 ALD.
We own a table-top ALD from Anric Technologies which is ideal for our lab-scale processes. It is thermal ALD and equipped with aluminum*, silicon*, titanium*, water, oxygen and ozone** precursors such that we can use it for depositing insulating layers of Al2O3 and SiO2 or semiconducting layers of TiO. The former is for example ideal for protecting/stabilizing our antennas.
*Strictly speaking the precursors are actually not aluminum, silicon or titanium but reactants such as trimethylaluminum.
**Produced using an ozone generator.
Keithleys + Micromanipulators
Finally, for electrically contacting and measuring the samples precisely, a collection of micromanipulators and sourcemeters are needed.
Keithleys 2604B and 2636B. 
Cascade Microtech Micromanipulators.
We own the Keithleys (now Tektronix) 2601A, 2604B and 2636B sourcemeters with a current measurement accuracy down to 120 fA at least for the latter one. Besides their low noise, an important feature for our measurements on nano-antennas is that one can limit the maximum possible current (e.g., to 10 nA) when applying a voltage. This prevented a lot of antennas of getting destroyed.
Micromanipulators we have from Cascade Microtech: the bigger and more precise DPP220 and the smaller DPP105 (formerly Suss Microtec PH100). The DPP220 offer Triax connection and we use them for electrically contacting our samples. The DPP105 we nowadays only use for transferring flakes.