Scanning Probe Microscopy (SPM)
Atomic Force Microscopy (AFM)
Atomic force microscopy is a scanning probe microscopy mode where images of surfaces are acquired using the mechanical, electrical, or magnetic interaction between a sharp tip (cantilever and tuning fork) and the surface. Many AFM modes have been published in the last 20 years, some of which are mainstream and others are more exotic.
In publications the trend goes towards the convergence of modes where existing approaches are combined and performed at the same time either to permit single scan operations, thus saving time, or to investigate new physics.
Zurich Instruments offers a comprehensive choice of electronics aimed to advanced SPM applications and the combination thereof.
|Mode||Description||MFLI + MF-PID
(5 MHz, 1 channel, 330 ns)
(50 MHz, 2 channels, 1 us)
|UHFLI + UHF-PID
(600 MHz, 2 channels, 30 ns)
|STM||Scanning tunneling microscopy||✓||✓ with HF2TA||-|
|STS IETS||Scanning tunneling spectroscopy (inelastic electron tunneling spectroscopy)||✓||✓||-|
|SNOM||Scanning near-field optical microscopy||✓||✓||✓|
|NC-AFM||Non-contact atomic force microscopy:||✓||✓||✓|
|MC-AFM||Multi-channel AFM, in-plane and out-of-plane channels||-||✓||✓|
|MF-AFM||Multi-frequency AFM||✓ with MD option||✓ with MF option||✓ with MF option|
|DFRT||Dual-frequency resonance tracking||-||✓||✓|
|AM-KPFM||Amplitude-modulated Kelvin probe force microscopy||✓ need 2 MFLI||✓||✓|
|FM-KPFM||Frequency-modulated Kelvin probe force microscopy||✓ with MD option||✓||✓|
|Dissipation KPFM||Convergence mode||-||✓||-|
|Time resolved AFM and STS||Convergence mode with pulsed lasers||-||-||✓ with BOX option|
|Band excitation||Wide-band probe excitation||-||-||✓ with AWG option|
|Dual-modulation||Convergence mode with 2 excitations||✓ with MD and MOD options||✓ with MF and MOD options||✓ with MF and MOD options|
|Electrical pump-probe||-||-||-||✓ with AWG option|
Scanning Tunneling Microscopy (STM)
As the very first instrument to demonstrate atomic resolution in real-space, from the IBM Zurich Laboratory, the STM still continues to demonstrate amazing resolution especially in the field of Scanning Tunneling Spectroscopy (STS), spin-polarized STM, or in combination with a light source (induced photo-current) or a photo-detector (light-emitting STM). Specially coated tips now even allow to perform experiment in liquid with an electrochemical STM and a bi-potentiostat.
High performance low-noise lock-in amplifier are therefore particularly valuable for multiple differential measurements such as dI/dV, d2I/dV2 or dI/dz measurements, Inelastic Electron Tunneling Spectroscopy (IETS) and 3D-Spectroscopy at large. Internal and external reference signals can also serve to enhance otherwise too weak signal from external modulation.
And, with the UHF Boxcar Averager, even time-resolved STS experiments can be addressed by averaging enough pulses to reach pA detectable current.
THz Scanning Near-field Microscopy (SNOM)
At the crossroad between laser and SPM experiments, Scanning Near-field Optical Microscopy (SNOM), hold many promises for both time and spatial resolution, especially in the field of plasmonics with the use of extraordinary optical transmission. With or without aperture, there is a large variety of different SNOM modes that originate from the interaction of light with mater at the nanoscale.
Many detection schemes, either homodyne, heterodyne or even pseudo-heterodyne (with interferometer), often require complex set-up that can be simplified with all-in-one multi-frequency lock-in amplifiers that allow for fine adjustment of all parameters and internal generation and demodulation of AM/FM signals.