Design, fabrication, and characterization of kinetic-inductive force sensors for scanning probe applications

• August K. Roos,
• Ermes Scarano,
• Elisabet K. Arvidsson,
• Erik Holmgren and
• David B. Haviland

Beilstein J. Nanotechnol. 2024, 15, 242–255, doi:10.3762/bjnano.15.23

• sidebands in the measured output microwave field SVV(ω). The thermal noise force is detected at these sidebands [8], where is the added noise of the detector, nc is the number of circulating intra-cavity photons in the microwave resonator, g0 is the single-photon electromechanical coupling rate, and α is a

• kinetic inductance of the nanowire. In our design, a sufficient requirement on g0 is that the motional sidebands due to the thermal noise force can be resolved above the noise floor of the detector. We prioritize a larger critical current of the nanowire to compensate a potentially smaller g0. For

• two microwave tones are applied at ωc ± ωm, while simultaneously actuating the cantilever through a coherent drive. Sidebands generated by the mechanical motion interfere with each other at the cavity’s resonant frequency ωc, either constructively or destructively, depending on the phase of the

Dual-heterodyne Kelvin probe force microscopy

• Benjamin Grévin,
• Fatima Husainy,
• Dmitry Aldakov and
• Cyril Aumaître

Beilstein J. Nanotechnol. 2023, 14, 1068–1084, doi:10.3762/bjnano.14.88

• in the existence of additional modulated component of the electrostatic force (or sidebands) at frequencies ω0 ± ωac. They stem from higher harmonic components in the capacitance term [16][18]: If we restrict ourselves to the first harmonic (n = 1), electrostatic force components emerge (we just

• describe the first set of sidebands, other exist at ω0 ± 2ωac) which are: It can be shown [18], that the Fourier coefficient at n = 1 is proportional to the second z-derivative of the capacitance (K1 ≡ C''z). Consequently, demodulating the amplitude of the sidebands gives access at a term that is

• there are 4 × n of them (instead of two sidebands for conventional AM-heterodyne KPFM): To avoid any confusion, in the following, the sidebands will be labelled as follow: As with conventional AM-heterodyne KPFM, the idea is to use the second mechanical resonance eigenmode of the cantilever to "boost" a

Spatial mapping of photovoltage and light-induced displacement of on-chip coupled piezo/photodiodes by Kelvin probe force microscopy under modulated illumination

• Zeinab Eftekhari,
• Nasim Rezaei,
• Hidde Stokkel,
• Jian-Yao Zheng,
• Andrea Cerreta,
• Ilka Hermes,
• Minh Nguyen,
• Guus Rijnders and
• Rebecca Saive

Beilstein J. Nanotechnol. 2023, 14, 1059–1067, doi:10.3762/bjnano.14.87

• leading to a better signal-to-noise ratio. The feedback applies a DC bias (VDC) matching the potential difference between the tip and the sample, which compensates for the electrostatic force. Therefore, the sidebands disappear. The value of VDC corresponds to the contact potential difference

Comparing the performance of single and multifrequency Kelvin probe force microscopy techniques in air and water

• Jason I. Kilpatrick,
• Emrullah Kargin and
• Brian J. Rodriguez

Beilstein J. Nanotechnol. 2022, 13, 922–943, doi:10.3762/bjnano.13.82

• . These mixing products have enhanced sensitivity to electrostatic forces at the expense of localization to small tip–sample separations. By choosing ωe such that the mixing products fall on the sidebands of ω1, the SNR is improved whilst enabling single-pass scanning. There are trade-offs here in that ωe

Impact of electron–phonon coupling on electron transport through T-shaped arrangements of quantum dots in the Kondo regime

• Patryk Florków and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2021, 12, 1209–1225, doi:10.3762/bjnano.12.89

• not only in sequential tunneling, but also in the Kondo regime where vibrational sidebands have been also observed [45][50][51][52][53][54]. The interplay of electron–phonon coupling and Kondo effect has been also studied theoretically [55][56][57][58][59][60]. In the present paper we analyze the

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• vibronic sidebands, which occur due to the simultaneous excitation of a vibrational mode upon charging [22][25][57][58][59][60][61]. The sidepeaks should thus obey the same symmetry as the parent orbital state [62][63][64]. In the simplest case, these excitations can be described within the Franck–Condon

Measurement of electrostatic tip–sample interactions by time-domain Kelvin probe force microscopy

• Christian Ritz,
• Tino Wagner and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2020, 11, 911–921, doi:10.3762/bjnano.11.76

• conventional frequency-modulated (FM-) KFM, the contributions at ωm and 2ωm are detected via lock-in techniques, either at the Δf output of a phase-locked loop (PLL) [12] or by detecting the sidebands of the cantilever oscillation [13]. In closed-loop FM-KFM, a feedback loop is employed to nullify the

A review of demodulation techniques for multifrequency atomic force microscopy

• David M. Harcombe,
• Michael G. Ruppert and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2020, 11, 76–91, doi:10.3762/bjnano.11.8

• frequencies components at fi and fi ± fm. The latter components are termed the upper and lower sidebands and are centered symmetrically around the carrier frequency as illustrated in Figure 1b. As the modulating frequency increases, the sidebands move away from the carrier up until the limit where the left

Long-term entrapment and temperature-controlled-release of SF₆ gas in metal–organic frameworks (MOFs)

• Hana Bunzen,
• Andreas Kalytta-Mewes,
• Leo van Wüllen and
• Dirk Volkmer

Beilstein J. Nanotechnol. 2019, 10, 1851–1859, doi:10.3762/bjnano.10.180

• (57.42 ppm) [34]. Additionally, small signals (marked by asterisks in Figure 4) to the left and right side of the main singlet represent spinning sidebands, which illustrates that the SF6 molecule is not completely freely rotating and that there is an interaction with the MOF host lattice. Computational

New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water

• Emmanuel I. Unuabonah,
• Robert Nöske,
• Jens Weber,
• Christina Günter and
• Andreas Taubert

Beilstein J. Nanotechnol. 2019, 10, 119–131, doi:10.3762/bjnano.10.11

• , indicating the presence of sp2-bonded carbon environments, specifically CH=CH2 moieties [35]. The weak bands at ≈215 and ≈35 ppm are rotation sidebands [36]. The 29Si MAS-NMR spectrum shows a set of low-resolution signals. The bands at −89, −100 and −126 ppm correspond to Q3 (1Al) [37], isolated silanol

Know your full potential: Quantitative Kelvin probe force microscopy on nanoscale electrical devices

• Amelie Axt,
• Ilka M. Hermes,
• Victor W. Bergmann,
• Niklas Tausendpfund and
• Stefan A. L. Weber

Beilstein J. Nanotechnol. 2018, 9, 1809–1819, doi:10.3762/bjnano.9.172

• can also be detected at the sidebands and of the mechanical oscillation at ωm. In particular, Equation 9 also contains a factor (UDC − UCPD) in analogy to Equation 7. This is the fundamental equation describing FM-KPFM. In the Appendix we show that the Fourier coefficient a1 is proportional to the

• distance reduces the lateral resolution and the image acquisition time is a factor of two longer, since every line needs to be scanned twice. In FM-KPFM, the force gradient-sensitive sidebands introduced in Equation 9 are used to measure the CPD. In the mode that we refer to as FM Sideband KPFM, the

• frequency of electrical excitation is lower than the first resonance ωE << ω0 while the detection is performed at ωm ± ωE with the mechanical oscillation frequency ωm at the first resonance. To decouple the detection of the sidebands from the mechanical carrier signal, ωm should be sufficiently high

Room-temperature single-photon emitters in titanium dioxide optical defects

• Kelvin Chung,
• Yu H. Leung,
• Chap H. To,
• Aleksandra B. Djurišić and
• Snjezana Tomljenovic-Hanic

Beilstein J. Nanotechnol. 2018, 9, 1085–1094, doi:10.3762/bjnano.9.100

• signals in the emission peaks by suppressing the contributions due to phonon sidebands. Conclusion This study investigated thin films, single crystals and nanopowders of TiO2 via confocal microscopy. For the first time, it has been observed that TiO2 defects exhibit antibunching behaviour within thin

Combined scanning probe electronic and thermal characterization of an indium arsenide nanowire

• Tino Wagner,
• Fabian Menges,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2018, 9, 129–136, doi:10.3762/bjnano.9.15

• -range electrostatic forces between the cantilever and sample structures, force-gradient sensitive detection is required [7][19]. In our setup, this is assured by direct demodulation of the sidebands that appear upon electrical modulation of the tip–sample electrostatic force [20]. Figure 2b shows the

• we detect modulations of the force gradient from the sidebands of the drive frequency fd in the deflection signal. The sidebands at fd ± fm are minimized by matching the dc tip bias to Ulcpd using a feedback loop. The sidebands at fd ± 2fm are proportional to the tip–sample capacitance gradient C

• ′′ and the KFM sensitivity. The feedback loop in our setup uses both pairs of sidebands and a Kalman filter to continuously estimate the surface potential and to avoid topographical artefacts [20]. Scanning thermal measurements of the InAs nanowire. (a) Setup for SThM measurements. (b) Topography and

A review of demodulation techniques for amplitude-modulation atomic force microscopy

• Michael G. Ruppert,
• David M. Harcombe,
• Michael R. P. Ragazzon,
• S. O. Reza Moheimani and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2017, 8, 1407–1426, doi:10.3762/bjnano.8.142

• components are termed the upper and lower sidebands and are centered symmetrically around the carrier frequency for fm < fc, illustrated in Figure 1b. As the modulating frequency increases, these sidebands move away from the carrier until they appear at DC and at 2fc for the limit where fm = fc. For the case

• where fm > fc, y(t) resembles a distorted wave with sidebands located at fm ± fc and can therefore no longer be considered an amplitude-modulated signal because the sidebands are no longer symmetrically located around the carrier frequency. For the application in AFM, this case is practically irrelevant

Kelvin probe force microscopy for local characterisation of active nanoelectronic devices

• Tino Wagner,
• Hannes Beyer,
• Patrick Reissner,
• Philipp Mensch,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2015, 6, 2193–2206, doi:10.3762/bjnano.6.225

• superior resolution of FM-KFM while maintaining robust topography feedback and minimal crosstalk, we introduce a novel FM-KFM controller based on a Kalman filter and direct demodulation of sidebands. We discuss the origin of sidebands in FM-KFM irrespective of the cantilever quality factor and how direct

• modulation; Kalman filter; Kelvin probe force microscopy; sidebands; Introduction Device performance of current nanoelectronic devices, and even more so of potential future generations including nanowires or molecular junctions, critically depends on transport properties varying on a length scale of a few

• practical approach to FM-KFM providing solutions to these issues. We remove the interdependence of topography and KFM feedbacks by focusing on the information contained in the sidebands produced by the electrostatic modulation [20]. Employing a commercially available lock-in amplifier, we detect these

Determining cantilever stiffness from thermal noise

• Jannis Lübbe,
• Matthias Temmen,
• Philipp Rahe,
• Angelika Kühnle and
• Michael Reichling

Beilstein J. Nanotechnol. 2013, 4, 227–233, doi:10.3762/bjnano.4.23

• demodulator tuned to the cantilever eigenfrequency. Effectively, the PLL projects the displacement noise power spectral density in the sidebands of the mode resonance into a range of frequencies fm starting at 0 Hz. Considering the transfer function of the demodulation and the transfer function of the PLL

Thermal noise limit for ultra-high vacuum noncontact atomic force microscopy

• Jannis Lübbe,
• Matthias Temmen,
• Sebastian Rode,
• Philipp Rahe,
• Angelika Kühnle and
• Michael Reichling

Beilstein J. Nanotechnol. 2013, 4, 32–44, doi:10.3762/bjnano.4.4

• presence of a tip–surface interaction, the resonance peak is shifted by the amount ( = −50 Hz in Figure 2) caused by the time-invariant part of the interaction. Additionally, sidebands appear that represent spectral components in Vz(t) created during scanning or spectroscopy. For simplicity, we assume

• power in the sidebands of Dz(f) into the frequency-shift power spectral density DΔf(fm), which can be represented as: The frequency shift Δf(t) varies on a time scale that in an imaging experiment is determined by the spatial periodicity of the scanned structure and the scanning speed, rather than by

• extracts the cantilever response to the tip–surface interaction from the sidebands of the cantilever-oscillation frequency spectrum (see Figure 2) and yields the signal power spectral density present in the sidebands, i.e., the displacement power spectral density Dz(f) is transformed to the frequency-shift

Diamond nanophotonics

• Katja Beha,
• Helmut Fedder,
• Marco Wolfer,
• Merle C. Becker,
• Petr Siyushev,
• Mohammad Jamali,
• Anton Batalov,
• Christopher Hinz,
• Jakob Hees,
• Lutz Kirste,
• Harald Obloh,
• Etienne Gheeraert,
• Boris Naydenov,
• Ingmar Jakobi,
• Florian Dolde,
• Sébastien Pezzagna,
• Daniel Twittchen,
• Matthew Markham,
• Daniel Dregely,
• Harald Giessen,
• Jan Meijer,
• Fedor Jelezko,
• Christoph E. Nebel,
• Rudolf Bratschitsch,
• Alfred Leitenstorfer and
• Jörg Wrachtrup

Beilstein J. Nanotechnol. 2012, 3, 895–908, doi:10.3762/bjnano.3.100

• sidebands on the lower energy side, shifted by 16 meV and 39 meV. The origin of this luminescence line is the 1.563 eV center, also sometimes referred to as the “NE8-center”. From this observation it can be concluded that nickel was not solely encapsulated during MWPECVD growth. In fact nickel-related color

• features became visible when PL measurements were performed at a temperature of 77 K as shown in Figure 14d. The bright line at a wavelength of 714 nm is the zero-phonon line of the emission. The ZPL is accompanied on the lower energy side by several phonon sidebands, which are nearly equidistantly spaced

• by 25 meV. Position of the ZPL, as well as of the sidebands, are in agreement with the so-called W5-center [16][23]. The same luminescence emission was reported in the past for diamond layers deposited by the hot-filament technique and accordingly by the DC-arcjet technique [16][23]. The W5-center

Repulsive bimodal atomic force microscopy on polymers

• Alexander M. Gigler,
• Christian Dietz,
• Maximilian Baumann,
• Nicolás F. Martinez,
• Ricardo García and
• Robert W. Stark

Beilstein J. Nanotechnol. 2012, 3, 456–463, doi:10.3762/bjnano.3.52

• with the lower eigenmode, resulting in symmetric sidebands. This results in the peaks f2 + f1 = 819.1 kHz and f2 – f1 = 592.0 kHz for direct mixing between the first and second eigenmodes and f2 + 2f1= 932.7 kHz and f2 – 2f1 = 478.4 kHz for the first eigenmode mixing with the second harmonic of the

• first eigenmode. We can even observe the f2 – 5f1 = 137.7 kHz peak for mixing with the fifth harmonic of the first eigenmode. However, the higher harmonic oscillations and the sidebands due to frequency mixing between the eigenmodes were smaller than the signals of f1 and f2 by at least two orders of

• eigenmodes. Sidebands of the second eigenmode are marked by “#”. Several harmonics (f1, 2f1, 4f1, 6f1, and 7f1) of the fundamental eigenmode can be observed above the noise level. Acknowledgements The authors thank E. C. Spitzner for sample preparation and Robert Magerle (both TU Chemnitz) for fruitful

Single-pass Kelvin force microscopy and dC/dZ measurements in the intermittent contact: applications to polymer materials

• Sergei Magonov and
• John Alexander

Beilstein J. Nanotechnol. 2011, 2, 15–27, doi:10.3762/bjnano.2.2

• response, which is detected by the phase signal or Y component signal of the LIA-1, is seen at the heterodyne frequencies ωmech ± ωelec. When the KFM servo is on, the heterodyne sidebands practically disappear and the DC voltage equals the contact potential difference. This AM–FM procedure is similar to