Artifacts in time-resolved Kelvin probe force microscopy

• Sascha Sadewasser,
• Nicoleta Nicoara and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2018, 9, 1272–1281, doi:10.3762/bjnano.9.119

• model system. In the experimental case, additional artifacts are observed due to constructive or destructive interference of the bias modulation with the cantilever oscillation. Also, in the case of light modulation, we demonstrate artifacts due to unwanted illumination of the photodetector of the beam

• cantilever eigenmodes, namely at 500 Hz and at 1428 Hz. We speculate that these deviations are due to possible capacitive cross talk between the ac voltage and the piezo cables or the photodetector. We can disregard these deviations since they are not related to the cantilever eigenmodes and have a different

• the flat CPD spectrum is again observed at the fundamental resonance frequency of the cantilever. This artifact can be explained by considering that part of the IM laser illumination reflects from the cantilever back side and the sample onto the position sensitive photodetector for the AFM detection

Surface characterization of nanoparticles using near-field light scattering

• Eunsoo Yoo,
• Yizhong Liu,
• Chukwuazam A. Nwasike,
• Sebastian R. Freeman,
• Brian C. DiPaolo,
• Bernardo Cordovez and
• Amber L. Doiron

Beilstein J. Nanotechnol. 2018, 9, 1228–1238, doi:10.3762/bjnano.9.114

• output edge where transmitted light is collected by a photodetector. Three polarization-maintaining optical fibers are supported by a silicon v-groove array and are optically aligned to the three waveguides permanently bonded to the chips. Each chip has two through-holes for fluidic access. Fluid lines

Non-equilibrium electron transport induced by terahertz radiation in the topological and trivial phases of Hg_1−xCd_xTe

• Alexandra V. Galeeva,
• Alexey I. Artamkin,
• Alexey S. Kazakov,
• Sergey N. Danilov,
• Sergey A. Dvoretskiy,
• Nikolay N. Mikhailov,
• Ludmila I. Ryabova and
• Dmitry R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 1035–1039, doi:10.3762/bjnano.9.96

• motivated by the application aspects related to the terahertz photodetector development [12]. In our recent paper [13], we have shown that photoconductivity in Hg1−xCdxTe solid solutions at 280 µm wavelength changes its sign across the topological transition from the inverted to the normal band structure

Electro-optical characteristics of a liquid crystal cell with graphene electrodes

• Nune H. Hakobyan,
• Hakob L. Margaryan,
• Valeri K. Abrahamyan,
• Vladimir M. Aroutiounian,
• Arpi S. Dilanchian Gharghani,
• Amalya B. Kostanyan,
• Timothy D. Wilkinson and
• Nelson Tabirian

Beilstein J. Nanotechnol. 2017, 8, 2802–2806, doi:10.3762/bjnano.8.279

• of a photodetector. When the He–Ne laser beam (632 nm) propagates through the LC cell placed between crossed polarizers (so that the direction of the polarization of the incident beam makes a 45° angle with the LC director), then the influence of an external electric field allows typical oscillations

AgCl-doped CdSe quantum dots with near-IR photoluminescence

• Pavel A. Kotin,
• Sergey S. Bubenov,
• Natalia E. Mordvinova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2017, 8, 1156–1166, doi:10.3762/bjnano.8.117

• solution of the same absorbance at 405 nm. IR-photoluminescence spectra were obtained with a MDR-23 monochromator with Ge photodetector calibrated with a 2600 K W-lamp. Transmission electron microscopy (TEM) studies were performed using JEOL JEM2100 and Tecnai G2 30 UT (LaB6) microscopes operated at 200

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

• Ionel Stavarache,
• Valentin Adrian Maraloiu,
• Petronela Prepelita and
• Gheorghe Iordache

Beilstein J. Nanotechnol. 2016, 7, 1492–1500, doi:10.3762/bjnano.7.142

• electron microscopy, electrical measurements in dark or under illumination and response time investigations. Finally, we demonstrate the feasibility of the procedure by the means of an Al/n-Si/Ge:SiO2/ITO photodetector test structure. The structures, investigated at room temperature, show superior

• , 400 and 500 °C, and no further thermal treatments were necessary after the deposition process. The paper also reports the influence of film structure on electrical and photoelectrical properties. Finally, we demonstrate the feasibility of the procedure by means of an Al/n-Si/Ge:SiO2/ITO photodetector

• of Ge-nps embedded in SiO2 thin film are summarized. The influence of the temperature on the photodetector test structure, fabricated on substrates at 300, 400 and 500 °C is also described. In Figure 1, the diffractograms recorded of thin films deposited by RF magnetron sputtering on substrates at

Efficiency improvement in the cantilever photothermal excitation method using a photothermal conversion layer

• Natsumi Inada,
• Hitoshi Asakawa,
• Taiki Kobayashi and
• Takeshi Fukuma

Beilstein J. Nanotechnol. 2016, 7, 409–417, doi:10.3762/bjnano.7.36

• showed the improvement of phase response compared to that measured with the noncoated AC55 cantilever (Figure 4d). The errors in the measured curves were mostly caused by a reflection of the excitation laser beam into the photodetector and the low excitation efficiency. The results suggest that the

Probing fibronectin–antibody interactions using AFM force spectroscopy and lateral force microscopy

• Andrzej J. Kulik,
• Małgorzata Lekka,
• Kyumin Lee,
• Grazyna Pyka-Fościak and
• Wieslaw Nowak

Beilstein J. Nanotechnol. 2015, 6, 1164–1175, doi:10.3762/bjnano.6.118

• knowledge of the normal cantilever spring constant and normal photodetector sensitivity. The nominal, normal spring constant was controlled by monitoring the resonant frequency of a thermally excited cantilever [17], carried out before functionalization with an antibody. Since the resonance frequency of the

• cantilever was almost constant (8.73 ± 0.07 kHz), the nominal value of the spring constant was used to measure the force value. The photodetector sensitivity (referred to here as normal PSD sensitivity) was determined from the slope of the force curve in the region of tip contact with the reference glass

• photodetector sensitivity. Both parameters are difficult to estimate using known methods [14][18], so here we propose a simple, alternative method that allows the measured signal (in V) to be directly converted into force units. The conversion factor is referred to here as the lateral PSD sensitivity. The

Graphene quantum interference photodetector

• Mahbub Alam and
• Paul L. Voss

Beilstein J. Nanotechnol. 2015, 6, 726–735, doi:10.3762/bjnano.6.74

• interference (QI) photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach–Zehnder interferometer (MZI), which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector

• nanoribbon; phase coherence; photodetector; quantum interference; resonant tunneling; Introduction Graphene, a single layer of carbon atoms arranged in a honeycomb lattice structure, has attracted much attention from researchers because of its exceptional electronic, mechanical and optical properties such

• structure as photodetector. In a MZI structure, an electron in the ground, transverse mode goes through the device with a transmittance of one (T = 1) due to constructive interference at energies corresponding to longitudinal resonant modes. At these resonant energies, the electrons have a high density of

Observation of a photoinduced, resonant tunneling effect in a carbon nanotube–silicon heterojunction

• Carla Aramo,
• Antonio Ambrosio,
• Michelangelo Ambrosio,
• Maurizio Boscardin,
• Paola Castrucci,
• Michele Crivellari,
• Marco Cilmo,
• Maurizio De Crescenzi,
• Francesco De Nicola,
• Emanuele Fiandrini,
• Valentina Grossi,
• Pasqualino Maddalena,
• Maurizio Passacantando,
• Sandro Santucci,
• Manuela Scarselli and
• Antonio Valentini

Beilstein J. Nanotechnol. 2015, 6, 704–710, doi:10.3762/bjnano.6.71

• applied voltage and excitation wavelength. The experiments are performed in the near-ultraviolet to near-infrared wavelength range. The high conversion efficiency of light radiation into photoelectrons observed with the presented layout allows the device to be used as a large area photodetector with very

• low, intrinsic dark current and noise. Keywords: heterojunction; multiwall carbon nanotubes; NDR; photodetector; tunneling; Introduction Negative differential resistance (NDR), where the current decreases as a function of voltage, has been observed in the current–voltage curves of several types of

• allows the carriers to cross the junction through the 2.4 V barrier, even at voltages of a few hundred mV. The optoelectronic properties of semiconducting carbon nanotubes are advantageous for the development of photodetector devices in the near-to-mid-infrared region (from ≈1 to ≈15 μm) [8]. The

A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

• Tobias Meier,
• Alexander Förste,
• Ali Tavassolizadeh,
• Karsten Rott,
• Dirk Meyners,
• Roland Gröger,
• Günter Reiss,
• Eckhard Quandt,
• Thomas Schimmel and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2015, 6, 451–461, doi:10.3762/bjnano.6.46

• read-out of a micro-fabricated cantilever [10][11]. However, the optical read-out contains bulky mechanical parts to focus a laser on the backside of the cantilever and to move the position sensitive photodetector (PSD) or a mirror which puts severe limits on a compact instrument design. Additionally

• , while adjusting the laser and photodetector is straightforward under ambient conditions under which all components are accessible, it is a challenge in environments such as vacuum or in fluids where the laser light gets scattered and refracted by multiple interfaces [12][13][14][15]. Furthermore

Photodetectors based on carbon nanotubes deposited by using a spray technique on semi-insulating gallium arsenide

• Domenico Melisi,
• Maria Angela Nitti,
• Marco Valentini,
• Antonio Valentini,
• Teresa Ligonzo,
• Giuseppe De Pascali and
• Marianna Ambrico

Beilstein J. Nanotechnol. 2014, 5, 1999–2006, doi:10.3762/bjnano.5.208

• light in the range from ultraviolet to near infrared. The device spectral efficiency obtained from the electrical characterization is finally reported and an improvement of the photodetector behavior due to the nanotubes is presented and discussed. Keywords: multi-wall carbon nanotubes; photodetectors

• comparable with those obtained for similar detectors with CNTs deposited by CVD [7][13][14][15]. In this work results from a photodetector based on CNTs spray-deposited on semi-insulating gallium arsenide (SI GaAs) are reported. In order to perform the morphological characterization of the resulting films

• . Specifically, a Thorlabs OSL1 white light source with optical fiber and a focusing lens were used to obtain a light spot on the photodetector while single wavelengths (400, 500, 600 and 700 nm) in the visible light range were selected by means of a filter set. For the UV characterization in the spectral range

Multi-frequency tapping-mode atomic force microscopy beyond three eigenmodes in ambient air

• Santiago D. Solares,
• Sangmin An and
• Christian J. Long

Beilstein J. Nanotechnol. 2014, 5, 1637–1648, doi:10.3762/bjnano.5.175

• oscillations while still being able to obtain relatively large amplitude readings at the photodetector (in units of voltage), which is also advantageous in terms of making these modes more sensitive [20]. In our experiments we set the free fundamental amplitude to approximately 100 nm and the next three modes

• to free amplitudes of approximately 2.9, 1.8, and 1.3 nm, respectively. With these settings the amplitude reading at the photodetector for all higher modes was approximately 10% of the reading for the fundamental eigenmode despite the comparatively small physical amplitude of the higher modes. Figure

Challenges and complexities of multifrequency atomic force microscopy in liquid environments

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 298–307, doi:10.3762/bjnano.5.33

• of higher eigenmodes and multiple-impact regimes [21][26], mass loading and fluid-borne cantilever excitation [19][23][24], discrepancies between the photodetector signal and the actual tip position for base-excited cantilever systems [24][28] and non-ideal spectroscopy curves (for example, curved

• with high accuracy (unfortunately this is not practical and only possible within highly controlled experiments) and the cantilever behaves in an ideal manner, it is not possible to determine the true tip trajectory from the photodetector reading. This is because the photodetector measures cantilever

• deflection (this can be approximated as tip position minus base position), not tip position. Figure 9 illustrates the photodetector readings that would be obtained for different values of the quality factor for a given second eigenmode tip oscillation (labeled as “Real”). Clearly spectroscopic measurements

Noise performance of frequency modulation Kelvin force microscopy

• Heinrich Diesinger,
• Dominique Deresmes and
• Thierry Mélin

Beilstein J. Nanotechnol. 2014, 5, 1–18, doi:10.3762/bjnano.5.1

• spectrum is measured at the output of the photodetector, without probe excitation. It is shown in Figure 5. The deflection noise spectrum Dn(f) contains a component due to thermal probe excitation plus a component due to detector output noise. The latter can be assumed to be constant over the relatively

• of noise gains as in Figure 1, it is necessary to present it by a noise source inserted between blocks APLL and FPLL. We shall now calculate how the displacement noise at the photodetector output transforms into phase noise at the phase detector output, which is represented by the phase noise

Kelvin probe force microscopy of nanocrystalline TiO₂ photoelectrodes

• Alex Henning,
• Gino Günzburger,
• Res Jöhr,
• Yossi Rosenwaks,
• Biljana Bozic-Weber,
• Catherine E. Housecroft,
• Edwin C. Constable,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2013, 4, 418–428, doi:10.3762/bjnano.4.49

• photodetector. To deduce the sample work function and monitor the integrity of the tip, a highly ordered pyrolytic graphite (HOPG) reference sample was measured before and after each measured specimen. The HOPG reference with a known work function of = 4.6 eV [65] was stored inside the glove box. Microscopic

• , Uniblitz). Laser light intensity was gradually reduced with different neutral density (ND) filters. Incident light intensity was measured at the sample location with a calibrated silicon photodetector (PD300-UV-SH, Ophir) and a power meter head (AN/2, Ophir). SPV spectroscopy was conducted on a commercial

High-resolution nanomechanical analysis of suspended electrospun silk fibers with the torsional harmonic atomic force microscope

• Mark Cronin-Golomb and
• Ozgur Sahin

Beilstein J. Nanotechnol. 2013, 4, 243–248, doi:10.3762/bjnano.4.25

• measuring its resonance frequency and quality factor (either by frequency sweeps or from the thermal peak in the noise spectrum). The gain of the torsional mode, defined as the photodetector signal corresponding to a unit amount of a quasi-static force acting on the tip, is determined by independently

Photoresponse from single upright-standing ZnO nanorods explored by photoconductive AFM

• Igor Beinik,
• Markus Kratzer,
• Astrid Wachauer,
• Lin Wang,
• Yuri P. Piryatinski,
• Gerhard Brauer,
• Xin Yi Chen,
• Yuk Fan Hsu,
• Aleksandra B. Djurišić and
• Christian Teichert

Beilstein J. Nanotechnol. 2013, 4, 208–217, doi:10.3762/bjnano.4.21

• macroscopically by means of time-resolved photoluminescence (TR-PL). The conventional steady-state PL and TR-PL were measured at 300 K. The monochromator used for both types of PL experiments has a linear dispersion of 0.8 nm/mm and was equipped with a photomultiplier tube as photodetector. The setup for the TR

Towards 4-dimensional atomic force spectroscopy using the spectral inversion method

• Jeffrey C. Williams and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 87–93, doi:10.3762/bjnano.4.10

• the operators F{} and F−1{} are the Fourier transform and the inverse Fourier transform, respectively. Recovery of the velocity in the Fourier domain allows averaging of multiple oscillation cycles as well as filtering of the data in order to reduce the noise typically seen in the photodetector signal

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

• beam deflection (OBD) setup were recently discussed in detail [3] and it was found that the major noise sources are shot noise arising from the photodetector as well as Johnson noise originating from the resistors in the preamplifier. Further noise is generated in the laser diode that is mainly quantum

• the optical beam-deflection scheme for measuring the cantilever displacement. Therefore, the laser-light power Ppd reaching the photodetector is a parameter characterising the system. Ppd is calculated from the sum signal of the PSD, which in turn depends on the spectral sensitivity of the photodiode

Characterization and properties of micro- and nanowires of controlled size, composition, and geometry fabricated by electrodeposition and ion-track technology

• Maria Eugenia Toimil-Molares

Beilstein J. Nanotechnol. 2012, 3, 860–883, doi:10.3762/bjnano.3.97

• containing Zn(NO3), Co(NO3), nitric acid, and polyvinylpyrrolidone (PVP) as an additive, 300 nm diameter Zn1−xCoxO nanowires with x ranging from 0.01 to 0.05 were grown [94]. The synthesis and properties of semiconducting CdTe and CdS nanowires are being investigated for their potential in photodetector and

Ultraviolet photodetection of flexible ZnO nanowire sheets in polydimethylsiloxane polymer

• Jinzhang Liu,
• Nunzio Motta and
• Soonil Lee

Beilstein J. Nanotechnol. 2012, 3, 353–359, doi:10.3762/bjnano.3.41

• normally exposed to an oxygen atmosphere to achieve high performance in UV photodetection. In this work we present results on a UV photodetector fabricated using a flexible ZnO nanowire sheet embedded in polydimethylsiloxane (PDMS), a gas-permeable polymer, showing reproducible UV photoresponse and

The atomic force microscope as a mechano–electrochemical pen

• Christian Obermair,
• Andreas Wagner and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2011, 2, 659–664, doi:10.3762/bjnano.2.70

• scanner and a beam-deflection detection system with a four-quadrant photodetector, allowing the simultaneous detection of topography and lateral forces. The AFM was used in the contact mode both for lithography and for imaging. Contact-mode V-shaped silicon nitride cantilevers with pyramidal tips, and

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

• amplifiers (LIAs) enabling multi-frequency measurements. The MAC III has three dual phase LIAs converting the AC inputs to amplitude and phase. These digitally-controlled analog LIAs have a broad bandwidth (up to 6 MHz) that cover the operational bandwidth of the photodetector employed in the microscope. A

• directly from the photodetector (AM–AM) or from the LIA-1 (AM–FM). The latter block scheme configuration is shown in Figure 1. In the AM–FM, the electrostatic interactions are excited by an AC voltage applied to the probe at ωelec = 3–5 kHz, which is within the bandwidth of ωmech. The electrostatic

• amplitude peak at 2ωmech is recorded and it is proportional to the force gradient signal, and therefore to d2C/dZ2. In the second configuration, the third LIA is connected directly to the photodetector and in this case the detected amplitude at 2ωelec is proportional to the electrostatic force and therefore