Advanced atomic force microscopy techniques V

• Philipp Rahe,
• Ilko Bald,
• Nadine Hauptmann,
• Regina Hoffmann-Vogel,
• Harry Mönig and
• Michael Reichling

Beilstein J. Nanotechnol. 2025, 16, 54–56, doi:10.3762/bjnano.16.6

• carry out a more detailed characterization of the optoelectronic properties. Rothhardt et al. map the local work function on graphene nanoribbons [7]. They experimentally investigate the charge transfer between a gold substrate and graphene nanoribbons and compare that to DFT calculations. Indeed, the

• doping of the graphene nanoribbons is reflected by the local work function. They also measure and calculate the local work function as a function of tip–sample distance and compare results to those of simple electrostatic models of a graphene nanoribbon, validating the overall approach of measurement and

Quantum-to-classical modeling of monolayer Ge₂Se₂ and its application in photovoltaic devices

• Anup Shrivastava,
• Shivani Saini,
• Dolly Kumari,
• Sanjai Singh and
• Jost Adam

Beilstein J. Nanotechnol. 2024, 15, 1153–1169, doi:10.3762/bjnano.15.94

• ), conduction/valence band density of states, electron/hole mobility, electron affinity, and work function can be derived from the initial band energy calculation. We calculated the effective masses of electrons and holes as = 0.167me and = 0.1768me, respectively, which are very close to the values ( = 0.17me

• the present calculation, we have calculated the average planar electrostatic potential along the plane as demonstrated in Figure 4. The figure depicts the vacuum energy level and the positions of HOMO and LUMO. The calculated work function and electron affinity for monolayer Ge2Se2 are about 3.313 and

• effective masses of electrons () and holes (), the effective DOS in the conduction and valence bands (Nc and Nv), electron and hole thermal velocities ( and ), electron and hole mobilities, electron affinity, and work function. We outline an efficient approach to calculating these device parameters briefly

Local work function on graphene nanoribbons

• Daniel Rothhardt,
• Amina Kimouche,
• Tillmann Klamroth and
• Regina Hoffmann-Vogel

Beilstein J. Nanotechnol. 2024, 15, 1125–1131, doi:10.3762/bjnano.15.91

• exotic nature of the charge carriers and to local confinement as well as atomic-scale structural details. The local work function provides evidence for such structural, electronic, and chemical variations at surfaces. Kelvin prove force microscopy can be used to measure the local contact potential

• difference (LCPD) between a probe tip and a surface, related to the work function. Here we use this technique to map the LCPD of graphene nanoribbons grown on a Au(111) substrate. The LCPD data shows charge transfer between the graphene nanoribbons and the gold substrate. Our results are corroborated with

• with respect to the Dirac point, the center of the Dirac cones [2]. The location of the Fermi level is a measure of the work function with respect to a different energy reference, the vacuum energy. This position can be tuned by gating [3] or by doping, for example, n-doping for graphene on SiC [4][5

Recent progress on field-effect transistor-based biosensors: device perspective

• Billel Smaani,
• Fares Nafa,
• Mohamed Salah Benlatrech,
• Ismahan Mahdi,
• Hamza Akroum,
• Mohamed walid Azizi,
• Khaled Harrar and
• Sayan Kanungo

Beilstein J. Nanotechnol. 2024, 15, 977–994, doi:10.3762/bjnano.15.80

• with a work function of 3.8 eV for source extensions and erbium silicide (ErSi1.7) materials for the drain and source regions. Two separated horizontal L-shaped nanocavity regions were implemented between the undoped silicon channel and the hafinium material. The oxide beneath the source extensions was

• plasma has been developed and implemented using appropriate metal work-function electrodes [98][99]. This structure is akin to the classical double-gate device, with the exception that the mid-region between the gates is etched out to capture biomolecules. The device reported by Chanda et al. can be

• doped junctionless tunnel FET (ED JL TFET)-based biosensors. This structure employs a single type of doping concentration, an appropriate work function, and a polarity-gate bias. Additionally, an N+ heavily doped silicon layer has been implemented with two separated gates to develop P+ and intrinsic

Effect of repeating hydrothermal growth processes and rapid thermal annealing on CuO thin film properties

• Monika Ozga,
• Eunika Zielony,
• Aleksandra Wierzbicka,
• Anna Wolska,
• Marcin Klepka,
• Marek Godlewski,
• Bogdan J. Kowalski and
• Bartłomiej S. Witkowski

Beilstein J. Nanotechnol. 2024, 15, 743–754, doi:10.3762/bjnano.15.62

• crystalline quality of the films. The implementation of the HT+RTA procedure significantly enhances the potential of CuO films for electronic applications. Key findings from Kelvin probe force microscopy analysis demonstrate the possibility of modulating the work function of the material. In addition

• performed under ambient conditions, which may have introduced surface states or absorbed water molecules on the surface of the investigated samples. Consequently, the obtained VCPD values and the resulting work function values are susceptible to additional errors, including those arising from the screening

• effect [49][50]. Despite the measurement conditions, it was still possible to qualitatively analyze changes in surface potential and work function based on the sample preparation method. The AFM, SCM, and KPFM data were analyzed using the Nanoscope Analysis 3.0 software (Bruker). The CuO films also

Reduced subthreshold swing in a vertical tunnel FET using a low-work-function live metal strip and a low-k material at the drain

• Kalai Selvi Kanagarajan and
• Dhanalakshmi Krishnan Sadhasivan

Beilstein J. Nanotechnol. 2024, 15, 713–718, doi:10.3762/bjnano.15.59

• low work function is placed in a high-k HfO2 layer in the source–channel region. The device is examined by the parameters Ioff, subthreshold swing, threshold voltage, and Ion/Ioff ratio. The introduction of a live metal strip in the dielectric layer closer to the source–channel interface results in a

• excellent improvement in TFETs, an on-current of 1.00 × 10−5 A/μm, an Ion/Ioff ratio of 7.14 × 1011, and a threshold voltage of 0.28 V. Keywords: dual low-work-function live strip (DLWLS); low-k dielectric spacer; low-work-function live strip (LWLS); Miller capacitance; molybdenum; subthreshold swing (SS

• previously published model, the proposed design uses a low-k material in the drain region to reduce Cgd. A metal strip with low work function placed at the source–channel interface causes an abrupt change in electron concentration, increasing the tunneling rate [14][15][16][17][18]. Molybdenum, used here as

Controllable physicochemical properties of WO_x thin films grown under glancing angle

• Rupam Mandal,
• Aparajita Mandal,
• Alapan Dutta,
• Rengasamy Sivakumar,
• Sanjeev Kumar Srivastava and
• Tapobrata Som

Beilstein J. Nanotechnol. 2024, 15, 350–359, doi:10.3762/bjnano.15.31

• sputtering for optoelectronic applications. A glancing angle of 87° is employed to grow films of different thicknesses, which are then exposed to post-growth annealing. Detailed local probe analyses in terms of morphology and work function of WOx films are carried out to investigate thickness-dependent

• fabricating WOx-based optoelectronic devices, including photovoltaic cells. Keywords: annealing; glancing angle sputter deposition; heterojunction; tungsten oxide; work function; Introduction Tungsten oxide (WOx; x ≤ 3) is a popular transition-metal oxide for various optoelectronic devices because of its

• -stoichiometric compositions and polymorphs, WOx usually behaves as an n-type semiconductor because an unintentional incorporation of a certain amount of reduced W cations is thermodynamically inevitable in these films [8]. It is, therefore, possible to tune the physicochemical properties, such as work function

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

• (CPD). If one considers a simple junction formed by a metallic AFM tip and a metallic sample, the CPD originates from the tip–sample work function difference. More generally, the CPD stems from the existence of electric charges and/or dipoles in the system under consideration. As a result, the

• compensation bias is applied to the tip. Then, provided that the effective work function of the tip remains constant during the measurement, any change in the KPFM compensation potential will strictly follow the change in the surface electrostatic potential without sign inversion (a local positive surface

Cross-sectional Kelvin probe force microscopy on III–V epitaxial multilayer stacks: challenges and perspectives

• Mattia da Lisca,
• José Alvarez,
• James P. Connolly,
• Nicolas Vaissiere,
• Karim Mekhazni,
• Jean Decobert and
• Jean-Paul Kleider

Beilstein J. Nanotechnol. 2023, 14, 725–737, doi:10.3762/bjnano.14.59

• × 1018 cm−3. Furthermore, in order to replicate the experiment, we have included a metal layer on the left of the n-type InP substrate. Under these conditions, the metal layer represents the contact between the sample holder and the n-type InP substrate. Finally, the work function of the metal was set to

• work function of GaInAsP:Zn is slightly larger (by 0.04 eV) than that of InP:Zn, and it is substantially larger (by 0.22 eV) than that of the GaInAs:Zn contact layer, which leads to a decrease and an increase of potential, respectively. It is important to note that due to the narrowness of the

Bismuth-based nanostructured photocatalysts for the remediation of antibiotics and organic dyes

• Akeem Adeyemi Oladipo and
• Faisal Suleiman Mustafa

Beilstein J. Nanotechnol. 2023, 14, 291–321, doi:10.3762/bjnano.14.26

• semiconductor and a noble metal with an appropriate work function. A unidirectional charge transfer is enabled by the Schottky potential barrier, increasing charge density and separation [72]. Shen et al. [166] created a Schottky junction by synthesising NiSe2 nanosheets on top of BiVO4 nanosheets using a

Utilizing the surface potential of a solid electrolyte region as the potential reference in Kelvin probe force microscopy

• Nobuyuki Ishida

Beilstein J. Nanotechnol. 2022, 13, 1558–1563, doi:10.3762/bjnano.13.129

• applied between the Au electrodes. The cross sections of the topography and CPD taken from the images in Figure 3a and Figure 3b are shown in Figure 3c and Figure 3d, respectively. The CPD values measured under this condition reflect the work-function difference across the surface [3]. The CPD values in

Induced electric conductivity in organic polymers

• Konstantin Y. Arutyunov,
• Anatoli S. Gurski,
• Vladimir V. Artemov,
• Alexander L. Vasiliev,
• Azat R. Yusupov,
• Danfis D. Karamov and
• Alexei N. Lachinov

Beilstein J. Nanotechnol. 2022, 13, 1551–1557, doi:10.3762/bjnano.13.128

• conditions, PDP is a wide-gap dielectric material and is characterized by the following parameters: band gap ≈4.3 eV, electronic work function ≈4.2 eV, electron affinity ≈2 eV, first ionization potential ≈6.2 eV. Experimental evaluations of the electronic parameters of PDP have been made earlier by various

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

• local contact potential difference (CPD) between the probe and the sample. This, in turn, allows the work function of the sample to be measured if the work function of the probe is known and vice versa. The mapping of local electrical properties of the interface is essential to further our understanding

Self-assembly of C₆₀ on a ZnTPP/Fe(001)–p(1 × 1)O substrate: observation of a quasi-freestanding C₆₀ monolayer

• Guglielmo Albani,
• Michele Capra,
• Alessandro Lodesani,
• Alberto Calloni,
• Gianlorenzo Bussetti,
• Marco Finazzi,
• Franco Ciccacci,
• Alberto Brambilla,
• Lamberto Duò and
• Andrea Picone

Beilstein J. Nanotechnol. 2022, 13, 857–864, doi:10.3762/bjnano.13.76

• tunneling microscopy/spectroscopy and ultraviolet photoemission spectroscopy. C60 nucleates compact and well-ordered hexagonal domains on top of the ZnTPP buffer layer, suggesting a high surface diffusivity of C60 and a weak coupling between the overlayer and the substrate. Accordingly, work function

• electronic gap equal to 3.75 eV. Finally, work function measurements have been performed to evaluate the charge transfer between the different layers constituting the heterostructure. Generally, electron transfer from the substrate (overlayer) to the overlayer (substrate) induces an increase (decrease) of

• the work function with respect to the bare surface. For the work function measurements, the sample has been biased with a voltage of 10 V to detect the onset of the secondary electrons. The onset position is determined as the intersection of the zero-current line and the tangent to the rising edge of

Direct measurement of surface photovoltage by AC bias Kelvin probe force microscopy

• Masato Miyazaki,
• Yasuhiro Sugawara and
• Yan Jun Li

Beilstein J. Nanotechnol. 2022, 13, 712–720, doi:10.3762/bjnano.13.63

• microscopy (AFM) [22]. KPFM measures the contact potential difference (CPD), which corresponds to the difference in work function between the tip and the sample, consecutively in darkness and under illumination, to determine the SPV values: SPV = CPDlight − CPDdark. In this method, the thermal drift between

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

• Ioana Marica,
• Fran Nekvapil,
• Maria Ștefan,
• Cosmin Farcău and
• Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

• combination with Au and Ag plasmonic nanomaterials, the 514, 785, and 1064 nm laser excitation lines and p-aminothiophenol (PATP) as a molecule to study the charge transfer in metal–semiconductor–molecule–metal model systems [66]. They concluded that ZnO, with its work function (WZnO) of 5.2 eV is in ohmic

• absorb the visible-emission energy, transferring the electrons to a higher energy state. Second, because the work function of ZnO is 5.2 eV and the work function of Au is 5.1 eV, ZnO can receive energy from Au until these two systems achieve a dynamic equilibrium. Thus, the electrons are transferred into

The effect of metal surface nanomorphology on the output performance of a TENG

• Yiru Wang,
• Xin Zhao,
• Yang Liu and
• Wenjun Zhou

Beilstein J. Nanotechnol. 2022, 13, 298–312, doi:10.3762/bjnano.13.25

• . Figure 1 was redrawn from [13] (ϕMetal: metal work function). Electrodeposition process. A PMMA plate was used as the electrodeposition liner. Contact and separation of Cu and PTFE. XRD diffraction patterns of the 16 samples after electrodeposition. Samples 1–8 of the 16 samples were screened and

Investigation of a memory effect in a Au/(Ti–Cu)Ox-gradient thin film/TiAlV structure

• Damian Wojcieszak,
• Jarosław Domaradzki,
• Michał Mazur,
• Tomasz Kotwica and
• Danuta Kaczmarek

Beilstein J. Nanotechnol. 2022, 13, 265–273, doi:10.3762/bjnano.13.21

• the relationship [51][52]: where hν = 21.22 eV is the He (I) photon energy, W = 16.01 eV is the width of the spectrum, that is, the energy difference between the VBM and the photoemission cutoff energy, and Eg = 2.80 eV is the bandgap energy calculated from the transmission spectrum. The work function

• constructed diagram assumes the presence of an additional wide TiO2 region in the middle of the prepared structure that corresponds to the region of high Ti concentration in the central part of the prepared (Ti–Cu)Ox thin film. The value of the work function (5.4 eV) and the width of the optical energy gap

• created on the border of Au or Ti6Al4V and the deposited (Ti–Cu)Ox thin film were electrical ohmic contacts, because the value of the work function of Au (ΦAu = 5.3 eV) or (ΦTi6Al4V = 4.3 eV) is greater than the value of the work function of the layer (Φ(Ti–Cu)Ox = 4.01 eV). This conclusion is supported

Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• material upon interaction with target gas analytes arise due to changes in, for instance, energy bands, surface charge, and work function caused by temperature, grain size, crystal plane energies, and doping [87][90][91]. Thus, there is no single sensing mechanism that explains all SMO gas sensors. The

Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review

• Keshav Nagpal,
• Erwan Rauwel,
• Frédérique Ducroquet and
• Protima Rauwel

Beilstein J. Nanotechnol. 2021, 12, 1078–1092, doi:10.3762/bjnano.12.80

• determined. Enhancing hole mobility: hole injection and transport layers The optimization of charge carrier injection also consists of reducing the driving voltage of the LED. For achieving this, holes should be readily injected from the high-work-function anode surface (e.g., ITO, SWNT), while the electrons

• should be injected from the low-work-function metal cathode surface. Therefore, HTL should possess excellent charge mobility and maintain morphological stability. Moreover, it should have an appropriate highest occupied molecular level (HOMO), ensuring a low energy barrier for hole injection from the

• HTL in OLED with the configuration ITO/PEDOT:PSS/SWNT–PVK nanocomposite/DCM-doped Alq3/Li:Al [47]. An efficient electron transport was also obtained from the Li:Al cathode (with work function of 2.9 eV) to the Alq3 layer due to its higher LUMO level (3.2 eV) in comparison to the Li:Al work function

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• substrate. Hurdax et al. reported that both charged and neutral species of sexiphenyl can co-exist on thin dielectric MgO films on Ag(100) [89]. Due to the changed work function of the substrate, charging of the adsorbates is enabled by electron tunneling. The charge transfer strongly influences the

• molecular conformation by planarizing the carbon backbone as well as the self-assembly. Hurdax et al. [89] suggested that work function measurements before and after the adsorption of molecules should give insight into the electronic and physical decoupling. It should be noted that metal oxide thin films

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

• topography, for example, adhesion, phase shift, stiffness, work function, or friction. In the following section, the utility of CNN in SPM is illustrated through several examples taken from the literature. Enhancing speed of image acquisition As discussed above, SPM imaging is inherently slow. One of the

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• ]. In addition, density functional theory has been used to model the effect of ion-induced defects on the electronic band structure of various 2D transition metal dichalcogenides [26][30][36], and band-excitation Kelvin probe microscopy has been used to probe the resulting changes in the local work

• function [30]. In several of these works, high-resolution scanning TEM (STEM) imaging has been performed to enable the analysis of the defects created on the atomic scale [26][29][30] (see, e.g., Figure 2c). Apart from 2D materials, thin-film samples have also been the subject of electronic property tuning

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• for atomic and molecular adsorbates owing to its local electronic trapping potential due to the in-plane electric field. We obtain work function (Φ) variations on the h-BN/Cu(111) superstructure of the order of 100 meV using two independent methods, namely the shift of field emission resonances and

• -BN/Cu(111) substrate. Keywords: decoupling layers; hexagonal boron nitride; local stiffness; Moiré superstructure; work function variation; Introduction Two-dimensional hexagonal boron nitride (h-BN) is among the list of materials that garnered tremendous interest following the exfoliation of mono

• ) [19][20], strain-induced highly corrugated layers for h-BN/Rh(111) [21][22][23], and template layers for molecules with strong local variations of the work function for h-BN/Ir(111) [24] are representative of such morphological diversity. We use low-temperature combined scanning tunnelling (STM) and

Interface interaction of transition metal phthalocyanines with strontium titanate (100)

• Reimer Karstens,
• Thomas Chassé and
• Heiko Peisert

Beilstein J. Nanotechnol. 2021, 12, 485–496, doi:10.3762/bjnano.12.39

• images are shown in Supporting Information File 1 (Figure S1). It was reported that the work function ϕF correlates strongly with the termination of the STO substrate surface [19]. For SrO-terminated STO(100) ϕF is significantly lower (3.1–3.6 eV) than for TiO2-terminated STO(100) (4.5–4.8 eV). The work

• (preparation II, experiment 2) and 4.15 eV (preparation II, experiment 1), although a very similar annealing procedure was applied. The work function variations indicate that different fractions of mixed terminations were prepared. The highest value of 4.15 eV points to a predominantly TiO2-terminated STO(100

• ) surface. We assume that the final work function depends critically on the diffusion of Sr ions during the final annealing step and thus slightly different evaporation conditions or sample temperatures influence the surface composition distinctly. The different termination for samples with different work