Piezotronic effect in AlGaN/AlN/GaN heterojunction nanowires used as a flexible strain sensor

• Jianqi Dong,
• Liang Chen,
• Yuqing Yang and
• Xingfu Wang

Beilstein J. Nanotechnol. 2020, 11, 1847–1853, doi:10.3762/bjnano.11.166

• synthesize AlGaN/AlN/GaN heterojunction NWs with controllable size. A single NW is transferred to a flexible poly(ethylene terephthalate) substrate and fixed by indium tin oxide electrodes to form an ohmic contact for the strain sensor. An external mechanical stress is introduced to study the performance of

• the fabricated piezotronic strain sensor. The gauge factor is as high as 30 under compressive or tensile stress, which indicates a high sensitivity of the strain sensor. Periodic strain tests show the high stability and repeatability of the sensor. The working mechanism of the strain sensor is

• investigated and systematically analyzed under compressive and tensile strain. Here, we describe a strain sensor that shows a great application potential in wearable integrated circuits, in health-monitoring devices, and in artificial intelligence. Keywords: AlGaN/AlN/GaN nanowires; flexible; piezotronic

Mapping of integrated PIN diodes with a 3D architecture by scanning microwave impedance microscopy and dynamic spectroscopy

• Rosine Coq Germanicus,
• Peter De Wolf,
• Florent Lallemand,
• Catherine Bunel,
• Serge Bardy,
• Hugues Murray and
• Ulrike Lüders

Beilstein J. Nanotechnol. 2020, 11, 1764–1775, doi:10.3762/bjnano.11.159

• -frequency (approx. 100 kHz) AC voltage (VAC) is applied to the tip–sample system in order to generate the movement of free carriers [18]. At a fixed DC bias, the capacitance variation is measured with a highly sensitive capacitance sensor with a sensitivity of approx. 10−19 F·Hz−1/2. In addition, the

• BEOL steps were accomplished. The SPM electrical measurements were performed in the cross section of the chip at the wafer level. In order to enable a stable and constant nanoscale contact between the sensor tip and the sample, a surface with a low roughness is required. For this purpose, the sample

Piezoelectric sensor based on graphene-doped PVDF nanofibers for sign language translation

• Shuai Yang,
• Xiaojing Cui,
• Rui Guo,
• Zhiyi Zhang,
• Shengbo Sang and
• Hulin Zhang

Beilstein J. Nanotechnol. 2020, 11, 1655–1662, doi:10.3762/bjnano.11.148

• /bjnano.11.148 Abstract The tracking of body motion, such as bending or twisting, plays an important role in modern sign language translation. Here, a subtle flexible self-powered piezoelectric sensor (PES) made of graphene (GR)-doped polyvinylidene fluoride (PVDF) nanofibers is reported. The PES exhibits

• effectively used, especially in human–computer interaction, such as gesture control, rehabilitation training, and auxiliary communication. Keywords: motion sensor; piezoelectric; polyvinylidene fluoride (PVDF); self-powered; sign language translation; Introduction Sign language, as a communication method

• are gradually showing rich application prospects in sign language learning and daily communication. A recently reported yarn-based stretchable sensor can already translate a large number of gestures into speech signals [1][2][3][4][5][6]. However, traditional real-time sign language translation

Selective detection of complex gas mixtures using point contacts: concept, method and tools

• Alexander P. Pospelov,
• Victor I. Belan,
• Dmytro O. Harbuz,
• Volodymyr L. Vakula,
• Lyudmila V. Kamarchuk,
• Yuliya V. Volkova and
• Gennadii V. Kamarchuk

Beilstein J. Nanotechnol. 2020, 11, 1631–1643, doi:10.3762/bjnano.11.146

• 10.3762/bjnano.11.146 Abstract Of all modern nanosensors using the principle of measuring variations in electric conductance, point-contact sensors stand out in having a number of original sensor properties not manifested by their analogues. The nontrivial nature of point-contact sensors is based on the

• mixture it is possible to get a functional dependence of the concentration of particular breath components on the amplitude of the sensor output signal. To demonstrate the feasibility of the proposed approach, we analyze the point-contact profiles from the breath of several patients and compare them with

• breath test. The present study indicates some necessary prerequisites for the design of fast detection methods using differential sensor analysis in real time, which can be implemented in various areas of science and technology, among which medicine is one of the most important. Keywords: breath profile

A self-powered, flexible ultra-thin Si/ZnO nanowire photodetector as full-spectrum optical sensor and pyroelectric nanogenerator

• Liang Chen,
• Jianqi Dong,
• Miao He and
• Xingfu Wang

Beilstein J. Nanotechnol. 2020, 11, 1623–1630, doi:10.3762/bjnano.11.145

• work, a new type of self-powered, high-performance ultra-thin p-Si/n-ZnO nanowire (NW) flexible photodetector (PD) and its application as full-spectrum optical sensor and pyroelectric nanogenerator (PENG) are demonstrated. The working mechanism of PDs for PENGs is carefully investigated and

Oxidation of Au/Ag films by oxygen plasma: phase separation and generation of nanoporosity

• Abdel-Aziz El Mel,
• Said A. Mansour,
• Mujaheed Pasha,
• Atef Zekri,
• Janarthanan Ponraj,
• Akshath Shetty and
• Yousef Haik

Beilstein J. Nanotechnol. 2020, 11, 1608–1614, doi:10.3762/bjnano.11.143

• oxide [1][2]. With the recent advancements in nanotechnology, this unique phenomenon received more attention since it can be used to generate nanoporous materials which are applicable in many areas, including drug delivery, biotechnology and sensor development. The interest in nanoporous materials

Walking energy harvesting and self-powered tracking system based on triboelectric nanogenerators

• Mingliang Yao,
• Guangzhong Xie,
• Qichen Gong and
• Yuanjie Su

Beilstein J. Nanotechnol. 2020, 11, 1590–1595, doi:10.3762/bjnano.11.141

• electronics [1][2][3][4][5] and wireless sensor networks is in high demand. Mechanical energy, which is widely distributed in the environment, is one of the most general power sources. The human body is a rich source of mechanical energy [6]. Muscle stretching, for example, converts biochemical energy into

Wafer-level integration of self-aligned high aspect ratio silicon 3D structures using the MACE method with Au, Pd, Pt, Cu, and Ir

• Mathias Franz,
• Romy Junghans,
• Paul Schmitt,
• Adriana Szeghalmi and
• Stefan E. Schulz

Beilstein J. Nanotechnol. 2020, 11, 1439–1449, doi:10.3762/bjnano.11.128

• by an in situ micro quartz crystal sensor. The particle formation has been done by thermal annealing under vacuum conditions. The wafers with Cu and Pt have been annealed in vacuo, while the wafers with Au and Pd were annealed ex situ. Each annealing consists of a heating phase, 30 min of annealing

Triboelectric nanogenerator based on Teflon/vitamin B1 powder for self-powered humidity sensing

• Liangyi Zhang,
• Huan Li,
• Yiyuan Xie,
• Jing Guo and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2020, 11, 1394–1401, doi:10.3762/bjnano.11.123

• measured open-circuit voltage was approximately 340 V. The TVB-TENG can be applied as a humidity sensor and exhibits a linear and reversible response to the relative humidity of the environment. Moreover, the change in relative humidity is also indicated by the change in luminosity of a set of light

• -emitting diodes (LEDs) integrated in the TVB-TENG system. The TVB-TENG proposed in this study illustrates a cost-effective method for portable power supply and sensing devices. Keywords: humidity sensor; self-powered system; triboelectric nanogenerators (TENGs); triboelectrification; vitamin B1

• , food safety, wearable electronics, and wireless sensor networks [1][2][3][4]. However, conventional power generation is needed to supply energy to these sensor networks, which leads to increased energy usage and adverse impacts on the environment. More specifically, the degradation of the urban

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

• Santiago H. Andany,
• Gregor Hlawacek,
• Stefan Hummel,
• Charlène Brillard,
• Mustafa Kangül and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2020, 11, 1272–1279, doi:10.3762/bjnano.11.111

• closed-loop sensor data obtained prior to imaging on the AFM scan head. For Figure 2, the AFM image shown was recorded at 300 mHz line rate at a resolution of 1024 pixels and 512 lines and over a scan range of 30 × 30 µm. The imaging mode used was off-resonance tapping (ORT) at a tapping rate of 2 kHz

Ultrasensitive detection of cadmium ions using a microcantilever-based piezoresistive sensor for groundwater

• Dinesh Rotake,
• Anand Darji and
• Nitin Kale

Beilstein J. Nanotechnol. 2020, 11, 1242–1253, doi:10.3762/bjnano.11.108

• – 76, India. 10.3762/bjnano.11.108 Abstract This paper proposes the selective and ultrasensitive detection of Cd(II) ions using a cysteamine-functionalized microcantilever-based sensor with cross-linked ᴅʟ-glyceraldehyde (DL-GC). The detection time for various laboratory-based techniques is generally

• only on absorption and fluorescence change and need dynamic acquisition [23]. A magnetic field powered pressure sensor proposed by Khan et al. [24] is capable of measuring pressure in the range of kilopascals but the suitability for the very low pressure caused by HMIs needs to be examined. A reduced

• graphene oxide (RGO)-based sensor and a microfluidic platform fabricated by [25][26][27] can be used with some surface modification for HMIs, but it is mostly capable of detecting in the micromolar range. A polymer-based microcantilever using an encapsulated piezoresistor has been proposed by Kale et al

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• fluorescence) of Alzheimer’s disease Aβ plaque accumulations. They observed that the nanoparticles are not only appropriate for imaging but they also prevent plaque accumulation and break the already formed aggregates. Feng et al. [163] developed a SPION sensor coupled with a synthetic protein that recognizes

A few-layer graphene/chlorin e6 hybrid nanomaterial and its application in photodynamic therapy against Candida albicans

• Selene Acosta,
• Carlos Moreno-Aguilar,
• Dania Hernández-Sánchez,
• Beatriz Morales-Cruzado,
• Erick Sarmiento-Gomez,
• Carla Bittencourt,
• Luis Octavio Sánchez-Vargas and
• Mildred Quintana

Beilstein J. Nanotechnol. 2020, 11, 1054–1061, doi:10.3762/bjnano.11.90

• 3.5 mm at 1000 nm excitation [7]. Figure 3b shows the singlet oxygen production tests of FLG-Ce6 and pristine Ce6. The singlet oxygen production is indirectly observed through the fluorescence intensity of the singlet oxygen sensor green reagent (SOSG), which is a singlet oxygen reporter. Thus, FLG

• presence 1 µM of a reporter molecule called singlet oxygen sensor green reagent (SOSG) to corroborate that FLG-Ce6 has the capacity to produce singlet oxygen and to quantify the production of the radical. The samples of FLG-Ce6 and Ce6, with the same concentration of Ce6, were subjected to a

• system characterization. a) UV–vis absorption spectra of pristine Ce6 (blue) and FLG-Ce6 (green). b) Singlet oxygen production assays. Singlet oxygen is indirectly observed through the fluorescence of the reporter molecule, singlet oxygen sensor green reagent; the higher fluorescence is related to higher

Highly sensitive detection of estradiol by a SERS sensor based on TiO₂ covered with gold nanoparticles

• Andrea Brognara,
• Ili F. Mohamad Ali Nasri,
• Beatrice R. Bricchi,
• Andrea Li Bassi,
• Caroline Gauchotte-Lindsay,
• Matteo Ghidelli and
• Nathalie Lidgi-Guigui

Beilstein J. Nanotechnol. 2020, 11, 1026–1035, doi:10.3762/bjnano.11.87

• -enhanced Raman scattering (SERS) sensors for the detection of 17β-estradiol. Gold deposition on top of a TiO2 surface leads to the formation of nanoparticles the plasmonic properties of which fulfil the requirements of a SERS sensor. The morphological and optical properties of the surface were investigated

• . Specifically, we demonstrate that the TiO2 background pressure during pulsed laser deposition and the annealing conditions offer control over the formation of Au nanoparticles with different sizes, shapes and distributions, yielding a versatile sensor. We have exploited the surface for the detection of 17β

• -estradiol, an emerging contaminant in environmental waters. We have found a limit of detection of 1 nM with a sensitivity allowing for a dynamic range of five orders of magnitude (up to 100 µM). Keywords: aptamer; Au nanoparticles; 17-β estradiol (E2); plasmonics; sensor; surface-enhanced Raman scattering

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

Beilstein J. Nanotechnol. 2020, 11, 1010–1018, doi:10.3762/bjnano.11.85

• ] started to thoroughly investigate the use of Te thin films as an active element in gas sensor manufacturing. They showed that microcrystalline Te thin films, grown by thermal vacuum evaporation, exhibit high sensitivity to low concentrations (ppm range) of nitrogen dioxide (NO2) even at room temperature

• time delay between measurements was 2 s, which was, simultaneously, much smaller than the sensor response time and much higher than the assessed dielectric relaxation time value. In order to transform the resistance signal into a voltage signal, the sample was connected in series to a load resistance

Wet-spinning of magneto-responsive helical chitosan microfibers

• Dorothea Brüggemann,
• Johanna Michel,
• Naiana Suter,
• Matheus Grande de Aguiar and
• Michael Maas

Beilstein J. Nanotechnol. 2020, 11, 991–999, doi:10.3762/bjnano.11.83

• load cell, a ULC-1N-535 model interface, and a ±1 mm length linear variable differential transformer (LVDT) sensor. System compliance was measured prior to testing. Twenty nine samples were tested under a travelling speed of 1 mm/min until failure. Before testing, the cross-sectional area of every

Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 922–937, doi:10.3762/bjnano.11.77

• then subsequently removed. For example, one method involves hanging weights from a material for some time, then removing the weights and allowing the material to recover. A strain gage or displacement sensor captures the deformation occurring during both phases, and the data is used for fitting. The

• data streams for post-processing, including Z-Raw (expected Z-position based on the voltage applied to the Z-piezo), Z-Sensor (measured Z-position), deflection, amplitude, and phase. The Z-Sensor measurement corresponds to the position of the piezo that controls the position of the base of the

• cantilever, and the time-derivative of the Z-Sensor data should be equal to the experimental approach velocity. To perform the fit procedure, only the deflection and Z-Sensor datasets are necessary. Figure 2a illustrates the shape of a common result as read from a force–distance curve output file. Because

Transition from freestanding SnO₂ nanowires to laterally aligned nanowires with a simulation-based experimental design

• Jasmin-Clara Bürger,
• Sebastian Gutsch and
• Margit Zacharias

Beilstein J. Nanotechnol. 2020, 11, 843–853, doi:10.3762/bjnano.11.69

• result, Choi et al. were able to measure an improved sensitivity for gas sensors made of tin oxide nanowires (SnO2 NWs) in comparison with powder-based SnO2 thin films [9]. For the use of NWs in electronic and sensor devices, freestanding NWs often have to be scratched off of the growth substrate

• laterally aligned NWs in sensor or electronic devices, control of the NW length is highly desired. Longer NWs can be contacted by means of standard lithography processes and do not require electron-beam lithography [12][28]. In the experiments presented in Figure 6, the process time was increased from 8 min

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• : dewetting; finite-difference time-domain (FDTD) method; plasmon resonance; silver (Ag) nanostructures; thin films; UV–vis absorption; Introduction In the last decade there has been significant development in sensor-related research regarding the application in optical, medical or biological areas [1][2][3

• plotted as a function of the time. We can observe how these amplitudes increase (sharp rise at approx. 0.9 fs after the start of the simulation), and then decay after the light is switched off and passed the sensor (beginning at approx. 20.9 fs). The absorbance calculated from the FDTD simulations is

Nanoarchitectonics: bottom-up creation of functional materials and systems

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2020, 11, 450–452, doi:10.3762/bjnano.11.36

• spectroscopy [37], bio-nanocomposites with clay nanoarchitectures for electrochemical devices [38], a biomimetic nanofluidic diode with polymeric carbon nitride nanotubes [39], and a unique Janus-micromotor applied as a luminescence sensor for sensitive TNT detection [40]. The variety of nanoarchitectonics

Using gold nanoparticles to detect single-nucleotide polymorphisms: toward liquid biopsy

• María Sanromán Iglesias and
• Marek Grzelczak

Beilstein J. Nanotechnol. 2020, 11, 263–284, doi:10.3762/bjnano.11.20

• offers an unprecedented sensitivity in native physiological media. Coupling these nanomaterial-based systems with enzymatic reactions can further increase the sensitivity and selectivity of a given sensor, leading to a scenario in which a tiny structural alteration of a biomolecule can be detected within

• the formation of the branched junctions altered the colloidal stability of the nanoparticles, leading to a gradual aggregation. The detection limit of this method was 7.7 fM. With the aim of improving the sensitivity of the plasmon-based colorimetric sensor, Ying and co-workers [82] have used gold

• . Specifically, the recently proposed protein corona sensor arrays in which the composition of protein corona reflects the presence of a given cancer enabled new venues in detecting diseases directly from a blood sample [140]. Moreover, the simultaneous detection of genetic mutations and disease-specific

Molecular architectonics of DNA for functional nanoarchitectures

• Debasis Ghosh,
• Lakshmi P. Datta and
• Thimmaiah Govindaraju

Beilstein J. Nanotechnol. 2020, 11, 124–140, doi:10.3762/bjnano.11.11

• involves critical optimization of the sensor platforms. The length of the target oligonucleotide sequence and the selective use of dopants significantly dominate the sensing efficacy [63]. In this context, electrochemical DNA sensors were developed by noncovalent layer-by-layer assemblies of phenothiazine

• dyes and DNA for the detection of damaged DNA [64]. Apart from biological samples, the identification of volatile organic compounds is another important field gaining the attention of researchers. Hairpin DNA and peptide sequences were integrated in a sensor design strategy to develop an optoelectronic

• thereby unambiguously circumvents the limitations associated with the earlier reports of DNA-based sensor systems. In our creation strategy, novel DNA nanoarchitectures were designed and developed for the sensing of mercury at subnanomolar levels, wherein adenine-conjugated naphthalenediimide (BNA) forms

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

• filter during operation it is recommended to fix Rk such that it reflects the standard deviation σ of the Gaussian noise in the input signal from the sensor y(t) (R = σ2). This leaves Qk as the only tuning variable that directly influences the Kalman gains and sets the tracking bandwidth. The functional

• in the presence of a much larger fundamental resonance frequency, emphasizing the need for strong noise sensitivity from the demodulator. Higher-harmonic AFM imaging was performed using an NT-MDT NTEGRA AFM on the second harmonic amplitude. The chosen cantilever (Budget Sensor TAP190G) has a

The effect of heat treatment on the morphology and mobility of Au nanoparticles

• Sven Oras,
• Sergei Vlassov,
• Simon Vigonski,
• Boris Polyakov,
• Mikk Antsov,
• Vahur Zadin,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2020, 11, 61–67, doi:10.3762/bjnano.11.6

• materials used in studies related to nanostructures. The small size and the enhanced properties of Au nanoparticles (NPs) compared to bulk gold make them important for the development of novel applications, for example, in the field of drug delivery [1], sensor technology [2], printing [3] and catalysis [4