Growth of a self-assembled monolayer decoupled from the substrate: nucleation on-command using buffer layers

• Robby Reynaerts,
• Kunal S. Mali and
• Steven De Feyter

Beilstein J. Nanotechnol. 2020, 11, 1291–1302, doi:10.3762/bjnano.11.113

• ], NaCl [40], CuN [41] and oxides [32][42] have been used. Typically, the ultrathin films of these wide band gap materials act as insulating layers while still allowing electron tunneling through them. Chemisorbed iodine layers have been used as passivating layers on metals such as Au for achieving

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• fill in this gap, this study presents a numerical simulation model that elucidates how the nanoparticle coating affects the nanoparticle agglomeration tendency as well as the effective magnetic relaxation time of the system. To simulate the self-organization of the colloidal nanoparticles, a stochastic

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• result is radically different from the data obtained for graphene/SiO2 [33]. In addition, hBN monolayers exhibit a high temperature stability, a low dielectric constant (ε = 3–4), and a high thermal conductivity [34]. The band gap of hBN is about 5.9 eV [35]. Furthermore, which is also important, hBN is

Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)

• Maximilian Schaal,
• Takumi Aihara,
• Marco Gruenewald,
• Felix Otto,
• Jari Domke,
• Roman Forker,
• Hiroyuki Yoshida and
• Torsten Fritz

Beilstein J. Nanotechnol. 2020, 11, 1168–1177, doi:10.3762/bjnano.11.101

• with the bands of the metal substrate, which results in changes of the intrinsic optical and electronic properties of the adsorbed molecule. This process is referred to as hybridization, which may be accompanied by the reduction of the HOMO–LUMO gap, the change of the energy-level alignment, and even

• through different ways such as the usage of wide-band-gap insulator thin films (e.g., oxides, alkali halides) [3][4], a molecular spacer layer [5][6], or sp2-hybridized two-dimensional interlayers (e.g., graphene and hexagonal boron nitride (h-BN)) [7][8]. The advantageous properties of an h-BN monolayer

• on metal single crystals are the high crystal quality, chemical inertness and the wide band gap of approx. 6 eV, which apparently renders h-BN a promising candidate for the decoupling of highly ordered molecular films [9][10]. However, indications for a significant hybridization of organic molecules

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• ) [18][19], while Au(111) is characterized by a surface-projected gap of sp-derived electron states [20]. Graphene on Pt(111) exhibits a considerable distance of 330 pm from the metal surface [21], which implies a weak graphene–metal hybridization. Adsorbates on graphene-covered Pt(111) are therefore

• signature up to 2 V. Both spectra do not exhibit a clear-cut gap region, i.e., a bias voltage range with nearly vanishing dI/dV signal. These observations reflect the strong hybridization of C42H28 with the Pt(111) surface and hamper the meaningful determination of a HOMO–LUMO gap width. Moreover, the

• lifetime of electrons injected into the LUMO [39]. Due to the absence of peaked orbital signatures a HOMO–LUMO gap width is hard to estimate. In a previous report, constant-current dI/dV data were presented for C42H28 on Au(111) and a HOMO–LUMO gap exceeding 3 eV was extracted [25]. A direct comparison to

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• beam. The near field localized at the tip apex enhances the optical field in the tip–sample gap by several orders of magnitude and simultaneously directs the emitted photons from the gap into the far field for detection. With recent demonstrations of a spatial resolution even at the angstrom level [25

• gap between the gold tip and the SiNW. A more quantitative investigation of the polarization angle-resolved emission patterns in Figure 6 will be further pursued. The results shown in Figure 4 and Figure 6 demonstrate that it is possible to combine the polarization angle-resolved experiments with a

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

• moiré pattern bears a topographic and an electronic modulation [38], we investigate the differential conductance (dI/dV) spectra on different locations (Figure 1d). We first examine the spectrum on the top site of the moiré structure. We observe a gap in the density of states, which is flanked by an

• the STM image in Figure 4a was recorded within the energy gap of the molecule, which explains the featureless shape. In order to determine the origin of each of the resonances, we recorded constant-height dI/dV maps at their corresponding energies (Figure 5). For the first resonance at positive bias

• essentially shows the same elliptical shapes of the molecules as the STM image recorded in the electronic gap (Figure 4a). Our DFT calculations suggest that the next higher unoccupied orbitals lie 3 eV above the LUMO and show a pattern of nodal planes that are absent in the experiment. Additionally, given the

Excitonic and electronic transitions in Me–Sb₂Se₃ structures

• Nicolae N. Syrbu,
• Victor V. Zalamai,
• Ivan G. Stamov and
• Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

• , may be associated with the Dember effect. The photoconductivity and photo-EMF spectra in the absorption edge region show a broad band with maximum values at 1.187 eV (Е⟂с) and 1.167 eV (Е||с) (Figure 3A) which are associated with the light absorption at the direct transitions in the interband gap

• and it does not refute the existence of indirect transitions given that more studies (like the ones made for Ge, Si, GaP, etc.) need to be performed in order to clarify those issues, ideally with purely grown crystals. We do not negate the existence of indirect transitions as we do not have such

A new photodetector structure based on graphene nanomeshes: an ab initio study

• Babak Sakkaki,
• Hassan Rasooli Saghai,
• Ghafar Darvish and
• Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

• particular, photodetectors based on graphene will have a large dark current due to the conductivity of graphene even without incident photons [2]. An energy gap in the band structure of graphene can be created using quantum confinement effects via creating graphene nanoribbons (GNRs) with a width of

• integer). This form of classification is based on the relation between the magnitude of the energy gap and the width of the AGNRs. The quantum confinement effect alters the bandgap energy in these nanostructures, which decreases with the increase of AGNR width (within each group). A comparison of the

• bandgap of the two structures, i.e., 7-AGNR and 8-AGNR with bandgap energies of 1.47 eV and 0.22 eV, respectively, shows that the bandgap depends on the dimer number or width of the nanoribbons. In other words, the addition of only one row of carbon atoms alters the energy gap about by 1.25 eV. We also

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an

• Following the line proposed in [4], an aluminium Al/AlOx/Al tunnel junction 0.4 × 2 µm2 was fabricated using a self-aligned shadow evaporation technique. Its current–voltage characteristic shown in the inset of Figure 1 (see below) has a well-defined hysteresis. The double voltage gap of the junction is

• excitation caused by a rapid decrease in the barrier, and remained constant until the appearance of a gap voltage due to thermal noise or quantum tunneling. The lifetime measurements were repeated at least 200 times for each value of the bias current. For a high-frequency experiment, a microwave signal was

Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films

• Vadim Morari,
• Aida Pantazi,
• Nicolai Curmei,
• Vitalie Postolache,
• Emil V. Rusu,
• Marius Enachescu,
• Ion M. Tiginyanu and
• Veaceslav V. Ursaki

Beilstein J. Nanotechnol. 2020, 11, 899–910, doi:10.3762/bjnano.11.75

• morphology, or in the formation of ZnO particles embedded into the ZnMgO matrix, respectively. Local compositional fluctuations leading to the formation of deep band tails in the gap were deduced from photoluminescence spectra. A model for the band tail distribution in the bandgap is proposed as a function

• in the formation of deep band tails in the gap. As for the samples annealed at 400 °C, the luminescence spectra revealed the presence of two PL bands, as shown in Figure 5, which is indicative of the presence of two components in the samples. The lower energy PL band comes from ZnO crystallites

• luminescence is excited by transitions between the states from the band tails. After excitation, the carriers relax to the minimum possible energy in the band tails, which determines the spectral position of the PL band. With increasing x value from 0 to 0.40, the deepness of band tails in the gap increases to

Three-dimensional solvation structure of ethanol on carbonate minerals

• Hagen Söngen,
• Ygor Morais Jaques,
• Peter Spijker,
• Christoph Marutschke,
• Stefanie Klassen,
• Ilka Hermes,
• Ralf Bechstein,
• Lidija Zivanovic,
• John Tracey,
• Adam S. Foster and
• Angelika Kühnle

Beilstein J. Nanotechnol. 2020, 11, 891–898, doi:10.3762/bjnano.11.74

• surface is followed by a region of low ethanol density, which has been referred to as a gap [15][17]. Beyond the gap, ethanol again arranges in vertical layers with a vertical distance of approximately 0.5 nm. In contrast to the first layer, however, it has been calculated that both the lateral order and

• , it appears very reasonable to assign this lateral structure to the ordered first layer of ethanol molecules. We note that the data of calcite and magnesite differ slightly when the tip is closer to the surface than the gap. While in the case of calcite a clear maximum (labelled 1 in Figure 1) is seen

• surface, pointing away from it. All atomic number density profiles show a pronounced minimum after this first layer of ethanol molecules on top of the calcite surface, the so-called “gap”. At larger distances from the surface, a second solvation layer can be identified by a peak in each of the atomic

A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer

• Pavel M. Marychev and
• Denis Yu. Vodolazov

Beilstein J. Nanotechnol. 2020, 11, 858–865, doi:10.3762/bjnano.11.71

• layer and the length of the S constriction are about the superconducting coherence length the CPR is single-valued and can be close to a sinusoidal shape. The product IcRn can reach Δ(0)/2|e| (Ic is the critical current of the junction, Rn is its normal-state resistance, Δ(0) is the superconductor gap

• of hot spots [7][8][9]. A relatively large gap Δ in superconducting banks plays an important role here because it prohibits heat dissipation from the S or the N link at low temperatures kBT < Δ and it leads to hysteresis even for S-N-S junctions of variable thickness [22]. This problem could be

• ) model [24][25] for the SN-S-SN junction. We suppose that electron temperature Te = T + δTe and phonon temperature Tp = T + δTp are close to the substrate temperature, δTe, δTp ≪ T and do not vary along the thickness. In the N layer the proximity-induced gap (minigap) is small, and, due to the inverse

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• orientation. To fill this gap in knowledge, here, we report room-temperature (RT) and low-temperature (LT) STM-based studies of the adsorption of nonplanar tin phthalocyanine (SnPc) molecules a rutile (110)-1 × 1 surface of TiO2. SnPc molecules appear on such a surface in two flat-lying geometries defined by

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• [32] (Figure 1b), and a van der Waals gap g = 3.36 Å [33] (Figure 1c, left). The crystal structure of WSe2 (0001) consists of a repetition of Se–W–Se trilayers, as depicted in Figure 1b. The irreducible representation of the phonon modes at the center of the Brillouin zone in WSe2 can be described by

• due to change in excitation energy, which has been analyzed in this study. The PL measurement in 1L WSe2 as P increased at T = 298 K (Figure 2e) depicts the variation of the excitonic A-peak, representing direct-gap transitions, where Eg (1L) = 1.61 eV. The shift of the A-peak towards lower energies

• substrate is shown in (c)-left, and the application of external stimuli such as laser power P and substrate temperature T. The interlayer gap g is shown as ≈3.36 Å. (e) The variation of the Raman spectra for the and A1g modes for mechanically exfoliated WSe2 for 1L, ML, and bulk. The mode exhibits a red

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• (LDA) computations suggests a lower indirect gap around 4 eV. Calculations with other methods suggest a higher value of about 5.95 eV [87]. In experiments, the variability of the properties is even larger. For example, stacking influences the electronic properties of h-BN [86]. The indirect bandgap is

Effect of Ag loading position on the photocatalytic performance of TiO₂ nanocolumn arrays

• Jinghan Xu,
• Yanqi Liu and
• Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

• solar energy harvesting in photovoltaic and photocatalytic applications owing to their extremely high visible-light absorption and tuned effective band gap. In this work, Ag-loaded TiO2 nanocolumn (Ag-TNC) arrays were fabricated based on anodic aluminum oxide (AAO) template by combining atomic layer

• conventional method (3.20 eV). This is attributed to the quantum size effect, according to which the Eg value of a semiconductor depends on physicochemical properties such as size, surface area, and crystalline phase [35]. When Ag particles are combined with TiO2, the band gap of the resulting Ag-TNC film is

Soybean-derived blue photoluminescent carbon dots

• Shanshan Wang,
• Wei Sun,
• Dong-sheng Yang and
• Fuqian Yang

Beilstein J. Nanotechnol. 2020, 11, 606–619, doi:10.3762/bjnano.11.48

• irreversible change in the energy gap induced by the annealing. It is known that the temperature dependence of the energy gap for the fluoresence of CDs can be expressed as [42] where Eg(T) is the energy gap at temperature T, S is the Huang–Rhys factor representing the coupling strength between exciton and

• phonon, is the phonon energy, and k is the Boltzmann constant. It is evident that increasing temperature leads to the decrease of the energy gap. The CDs become conductive at temperatures larger than the critical temperture and lose the PL charactersistic, as demonstrated by the annealed-CDs due to

• the irreversible change in the energy gap at high temperatures. The PL characteristics of CDs depend on the structure and composition of the CDs, as shown by the FTIR spectra of the HTC-CDs, annealed-CDs, and LA-CDs-10% (Figure 7). The FTIR spectrum of the HTC-CDs is similar to that of LA-CDs-10

Identification of physicochemical properties that modulate nanoparticle aggregation in blood

• Ludovica Soddu,
• Duong N. Trinh,
• Eimear Dunne,
• Dermot Kenny,
• Giorgia Bernardini,
• Ida Kokalari,
• Arianna Marucco,
• Marco P. Monopoli and
• Ivana Fenoglio

Beilstein J. Nanotechnol. 2020, 11, 550–567, doi:10.3762/bjnano.11.44

• ; size; surface chemistry; Introduction Nanomedicine is one of the most exciting fields of research in the branch of nanotechnology as it has the potential to generate practical and effective solutions to tackle chronic diseases and to solve unmet clinical challenges. However, a tremendous gap exists

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

• exhibit transitions between separated bands. This can be observed in Ag, where a transition of electrons induced by visible light can take place between the d band and the sp band [6][7][28][29][30][31][32]. The width of the gap between s band and d band is in this case in the range of 3.7–3.9 eV [7][29

High dynamic resistance elements based on a Josephson junction array

• Konstantin Yu. Arutyunov and
• Janne S. Lehtinen

Beilstein J. Nanotechnol. 2020, 11, 417–420, doi:10.3762/bjnano.11.32

• energy gap. Consequently, in our approach, we opted for a non-dissipative (superconducting) high-impedance environment under zero magnetic field. Our quasi-one-dimensional arrays of SIS junctions contain loops forming SQUIDs (Figure 1). The Josephson current is very small (Figure 2a), Ic < 10 pA, and

• application of the magnetic field only monotonically suppresses the superconducting gap. The corresponding I–V dependence can be understood as a tunnel characteristic of multiple SIS junctions connected in series. The I–V characteristics (Figure 2a) with a gap of ≈10 mV corresponds well with 25 SIS junctions

• connected in series, each being a Al–AlOx–Al junction with a gap of about 400 µV. The charging energy, Ec = e2/2C, of each SIS contact (considering it to be a plate capacitor with dielectric constant ε ≈ 10, area 100 × 100 nm and distance between plates ≈2 nm) is about two orders of magnitude higher than

Synthesis and enhanced photocatalytic performance of 0D/2D CuO/tourmaline composite photocatalysts

• Changqiang Yu,
• Min Wen,
• Zhen Tong,
• Shuhua Li,
• Yanhong Yin,
• Xianbin Liu,
• Yesheng Li,
• Tongxiang Liang,
• Ziping Wu and
• Dionysios D. Dionysiou

Beilstein J. Nanotechnol. 2020, 11, 407–416, doi:10.3762/bjnano.11.31

• the treatment of organic contaminants in wastewater is in urgent need owing to the deterioration of the ecological environment [1]. Metal oxides, such as ZnO [2], TiO2 [3], Fe2O3 [4], and CuO [5], have been demonstrated to be promising photocatalysts. In particular, the band gap energy (Eg) of the p

• spectra were collected to study the optical properties of the samples. As shown in Figure 5a, the CuO/tourmaline composite exhibited higher optical adsorption than that of pure CuO, due to the plasmon resonance of the tourmaline units [24]. The band gap of CuO and CuO/tourmaline composite was calculated

• to be Eg = 1.38 eV and Eg = 1.31 eV, respectively (Figure 5b). The lower band gap of the CuO/tourmaline composite suggested a higher utilization efficiency of light [32]. Various measurements were employed to investigate the effect of tourmaline on the separation of photoinduced charge carriers. The

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• transition metals, as well as Ag and Au. However, most studies have examined single-atom adsorption or adsorbed nanoparticles of noble metals. This means there is a knowledge gap in terms of thin film nucleation on 2D materials. To begin addressing this issue, we present in this paper a first-principles

• increases [2]. Experimental methods for controlling the formation of sulfur vacancies in the MoS2 monolayer have also been developed [33], and this would allow for the targeted use of S vacancies to enhance desired properties such as adsorption energy. In this study we aim to fill the gap in the literature

• (DOS) analysis shows the emergence of mid-gap states, indicating that the system is changing from semiconducting to metallic as Cu atoms are adsorbed, making it suitable for application as a Cu diffusion barrier. Computational Methods All calculations, for bulk MoS2 and the 2D monolayer, were carried

Poly(1-vinylimidazole) polyplexes as novel therapeutic gene carriers for lung cancer therapy

• Gayathri Kandasamy,
• Elena N. Danilovtseva,
• Vadim V. Annenkov and
• Uma Maheswari Krishnan

Beilstein J. Nanotechnol. 2020, 11, 354–369, doi:10.3762/bjnano.11.26

• using cells treated with free siRNA or polyplex for 48 h (Figure 10). It is observed that the scratched gap was filled more slowly in cells treated with free siRNA when compared with the control cells. This was even more delayed in cells treated with the polyplex and pristine PVI. It is likely that the

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

• Levente Máthé and
• Ioan Grosu

Beilstein J. Nanotechnol. 2020, 11, 225–239, doi:10.3762/bjnano.11.17

• for the gapped graphene electrodes within the massless gap scenario. The systems present a high heat-to-electricity conversion efficiency at low temperature, for which the phonon contribution can be neglected [38][39]. The analytical approaches to Kondo physics of magnetic impurities in graphene