Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 44: Scanning probe techniques: Method development – Poster

O 44.8: Poster

Dienstag, 10. März 2026, 14:00–16:00, P2

all-in-one preparation stage of STM/AFM QPlus sensors for ultrahigh vacuum — •reza habibipour, jakob pelster, marco pratzer, michiel reul, and markus morgenstern — II. Institute of Physics B, RWTH Aachen University and JARA-FIT, Germany

QPlus sensors enable the combination of atomic force microscopy (AFM) and scanning tunneling microscopy (STM) with high resolution. We developed a compact preparation stage for positioning, glueing, annealing and tip etching of wires with diameters down to 7.5 um and length down to 200 um. The QPlus sensors are based on a piezoelectric quartz tuning fork with nominal frequency of 32.6 kHz. A tip wire is attached to one prong with the other prong is fixed to a ceramic block on the ultrahigh-vacuum (UHV) sample holder. Two tuning-fork contacts connect to the sample plate for AFM oscillatory function and for STM current. Sensor preparation utilizes a long-working-distance optical microscope (~6 cm) and micrometer manipulators for precise glue and wire positioning. A heater is used to cure the glue. A tungsten-carbide flush cutter trims the wire to within 0.2 mm of the prong edge. Alternatively, an etching ring is employed for tip shaping. Afterwards contacts can be checked in-situ by a Keithley instrument. Q-factors at room temperature and UHV amount to 16.000. The resulting QPlus sensors will be employed in a 300 mK STM/AFM cryostat mostly for maneuvering towards stacks of 2D materials by AFM prior to STM measurements.

Keywords: QPlus sensors; scanning tunneling microscopy; 2D materials; atomic force microscopy; surface microscopy