Scanning Tunneling Microscopy (STM) is a technique that allows its user to make scans of the surface topography of a sample. Via a capacitive approach, a tip is brought in close proximity to the...Show moreScanning Tunneling Microscopy (STM) is a technique that allows its user to make scans of the surface topography of a sample. Via a capacitive approach, a tip is brought in close proximity to the sample, by which eventually a tunneling current is measured that is used to obtain a scan. It can be interesting to do STM experiments at extremely low temperatures (< 4 K), which can be done by placing an STM into a dilution refrigerator. It is difficult to do so in a dry dilution refrigerator, because of the pulse tube system that brings lots of mechanical vibrations. This research shows the performance of the newly developed `PAN-motor' and `linear cryo-walkers', two new types of motors for STM-approaches at extremely low temperatures. The cryo-walkers in particular have allowed for a full approach at millikelvin temperatures due to its low heat dissipation, whereas this approach normally has to be done above 4 K. By realizing dry dilution refrigerator STM, more research at millikelvin temperatures would be made possible, due to these dry dilution refrigerators being closed systems, allowing for time-unlimited measurements. This advancement could allow for experiments with low T_c superconductors, or shot noise experiments with the new Multi-LC circuit, that has shown to enable the measurement of shot noise with a total measuring time of \tau \approx 98 h.Show less
The low noise amplifier from Bastiaans et al. [1] is improved by increasing the bandwidth, such that measurement time is reduced. Instead of a single common-source transistor, a cascode setup is...Show moreThe low noise amplifier from Bastiaans et al. [1] is improved by increasing the bandwidth, such that measurement time is reduced. Instead of a single common-source transistor, a cascode setup is used. A common-source is followed by a common-gate which is followed by a common-drain. The gain (V/V) of the amplifier is estimated to be 22. The cascoding reduces the miller capacitance from 22pF to approximately 2pF. The input noise current is estimated to be 19fA/√Hz and the voltage noise 0.2nV/√Hz. The power dissipation is estimated at 2mW.Show less
