Effect of localized helium ion irradiation on the performance of synthetic monolayer MoS₂ field-effect transistors

• Jakub Jadwiszczak,
• Pierce Maguire,
• Conor P. Cullen,
• Georg S. Duesberg and
• Hongzhou Zhang

Beilstein J. Nanotechnol. 2020, 11, 1329–1335, doi:10.3762/bjnano.11.117

• repeatedly by adjacent line scans, increasing the effective delivered dose and shifting that region to a more acceptor-rich area. This leads to the observed ambipolar gate response for large IR values. The formation of these back-to-back heterojunctions may result in unconventional charge transport phenomena

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

• -doped silicon nanowires (SiNWs). A rational strategy to obtain radial homo- and heterojunctions is to overcoat the as-grown nanowires within the same reaction chamber by implementing a conventional CVD process (e.g., thermal SiH4-CVD) yielding core–shell nanowires [14]. Although ideal epitaxial growth

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

• contact on the p-type Si substrate. Figure 9 and Figure 10 compare the current–voltage characteristics of p-Si/n-Zn1−xMgxO heterojunctions for two films deposited by spin coating with x values of 0.10 (Figure 9) and 0.40 (Figure 10). One can see from Figure 9b and Figure 10b that in both cases the current

• , the investigated heterojunctions work as photodetectors at forward bias, while a classical p–n junction should function as a photodetector at reverse bias. Since the current–voltage characteristics are fit to straight lines in the log–log coordinates, it means that they correspond to a power function

• heterojunction with a Zn0.6Mg0.4O film, the current–voltage characteristics fit to the MG law both in the dark and under illumination (see Figure 10c). These observations suggest that the investigated heterojunctions work at forward bias as injection photodiodes [53][54]. A more detailed investigation of

Epitaxial growth and superconducting properties of thin-film PdFe/VN and VN/PdFe bilayers on MgO(001) substrates

• Wael M. Mohammed,
• Igor V. Yanilkin,
• Amir I. Gumarov,
• Airat G. Kiiamov,
• Roman V. Yusupov and
• Lenar R. Tagirov

Beilstein J. Nanotechnol. 2020, 11, 807–813, doi:10.3762/bjnano.11.65

• ferromagnets to improve the operation characteristics of superconductor–ferromagnet–insulator heterojunctions for superconducting spintronics applications. For example, cubic superconducting MoNx, which is a Josephson junction technology material [4][5][46], exhibits a good epitaxial match with Pd1−xFex alloys

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

• addition, since the chemical transformation of MB molecules occurs at the Ag–TiO2 interface, Ag is more easily oxidized, which damages the long-term stability of the Ag–TiO2 heterojunctions [46]. Taken together, these factors can explain the difference of catalytic efficiency between AFT and ACT

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• heterojunctions of armchair graphene and boron nitride nanoribbons, exhibiting negative differential resistance is proposed. Low-bandgap armchair graphene nanoribbons and high-bandgap armchair boron nitride nanoribbons are used to design the well and the barrier region, respectively. The effect of all possible

• semiconductors is degraded by dislocations and lattice mismatch at the interface of different bandgap materials, the RTDs based on heterojunctions between armchair graphene nanoribbons (AGNRs) and armchair boron nitride nanoribbons (ABNNRs) have shown superior performance because of the very low lattice mismatch

• between graphene and hBN [3]. However, inevitable interfacial defects located at the interface of Gr/hBN heterojunctions, including point defects (single vacancies and substitutional defects) and topological defects can alter the electronic properties of Gr/hBN heterostructures and, consequently, the

Preparation, characterization and photocatalytic performance of heterostructured CuO–ZnO-loaded composite nanofiber membranes

• Wei Fang,
• Liang Yu and
• Lan Xu

Beilstein J. Nanotechnol. 2020, 11, 631–650, doi:10.3762/bjnano.11.50

• , and hydrothermal synthesis parameters on morphology, structure, and properties of the CNFMs were investigated, and the optimal process parameters were determined. CuO–ZnO heterojunctions were successfully grown on the surface of PVDF/PAN CNFMs and were applied in the photocatalytic degradation of

• methyl orange. In addition, a large number of p–n heterojunctions are formed due to the combination of p-type CuO and n-type ZnO. Under UV irradiation, the excited electrons in the CB of CuO can easily move to the CB of ZnO, whereas the holes in the VB of ZnO can migrate into the VB of CuO. Thus, the

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• PTB7 and PC71BM is subsequently investigated by recording point-spectroscopy curves as a function of the optical power at the cathode and by mapping 2D time-resolved images of the surface photovoltage of the bare organic active layer. Keywords: bulk heterojunctions; Kelvin probe force microscopy (KPFM

• -processed organic donor–acceptor blends called bulk heterojunctions (BHJ), for polycrystalline direct bandgap semiconductors such as CdTe, CuInxGa(1−x)Se2 and Cu2ZnSnS4 and for hybrid organic–inorganic perovskite solar cells. Whatever material used, improving the performance of the solar cell requires a

• -based devices, hybrid perovskite thin films and single crystals as well as type-II van der Waals heterojunctions based on transition metal dichalcogenides. Experimental Nc-AFM and pp-KPFM Noncontact-AFM (nc-AFM) experiments were performed with a ScientaOmicron VT-AFM setup in UHV at room temperature (RT

Recent progress in perovskite solar cells: the perovskite layer

• Xianfeng Dai,
• Ke Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2020, 11, 51–60, doi:10.3762/bjnano.11.5

• perovskites prepared by the method mentioned above still suffer from lower partial charge-carrier extraction efficiency compared with the 3D devices. Xing et al. [62] introduced a new 2D/3D device with phase-segregated vertical heterojunctions of 2D and 3D perovskites (Figure 4a) by incorporating long

• C6H18N2O2PbI4 (EDBEPbI4) chains into 3D perovskites. The 2D/3D perovskites solved the discrepancy between PCE and stability. XRD patterns and UV–vis absorption spectra, retracing the formation of such heterojunctions, are shown in Figure 4b and Figure 4c. Doping with EDBEPbI4 gradually increases the grain size

Synthesis and acetone sensing properties of ZnFe₂O₄/rGO gas sensors

• Kaidi Wu,
• Yifan Luo,
• Ying Li and
• Chao Zhang

Beilstein J. Nanotechnol. 2019, 10, 2516–2526, doi:10.3762/bjnano.10.242

• by deposition processes [22][23]. Furthermore, the combination of metal oxides with graphene or its derivatives can enhance the gas sensing capability by improving the adsorption/desorption ability of the incorporated molecules, the transfer of carriers and the formation of local heterojunctions [24

• Fermi energy levels equalize when two semiconducting systems are in contact via the transfer of carriers. Consequently, heterojunctions and regions of electron depletion will be formed at the interface between rGO, which is a p-type semiconductor, and ZnFe2O4, an n-type semiconductor. In addition, there

First principles modeling of pure black phosphorus devices under pressure

• Ximing Rong,
• Zhizhou Yu,
• Zewen Wu,
• Junjun Li,
• Bin Wang and
• Yin Wang

Beilstein J. Nanotechnol. 2019, 10, 1943–1951, doi:10.3762/bjnano.10.190

• built a set of pure monolayer zigzag and armchair BP nanodevices and investigated their pressure-related electric properties from first principles. Comparing to metal–BP heterojunctions, pure BP devices have advantages including simple structure, easy preparation, smooth continuous interface, and

Selective gas detection using Mn₃O₄/WO₃ composites as a sensing layer

• Yongjiao Sun,
• Zhichao Yu,
• Wenda Wang,
• Pengwei Li,
• Gang Li,
• Wendong Zhang,
• Lin Chen,
• Serge Zhuivkov and
• Jie Hu

Beilstein J. Nanotechnol. 2019, 10, 1423–1433, doi:10.3762/bjnano.10.140

• door for potential applications in gas recognition and detection. Keywords: Mn3O4/WO3 composites; heterojunctions; working temperature; gas sensing; selectivity; Introduction Tungsten oxide (WO3) is a highly stable, classical transition metal oxide. When synthesized, WO3 usually presents a yellowish

Photoactive nanoarchitectures based on clays incorporating TiO₂ and ZnO nanoparticles

• Eduardo Ruiz-Hitzky,
• Pilar Aranda,
• Marwa Akkari,
• Nithima Khaorapapong and
• Makoto Ogawa

Beilstein J. Nanotechnol. 2019, 10, 1140–1156, doi:10.3762/bjnano.10.114

• semiconducting NPs on inert porous solids of large specific surface area is considered to be beneficial for the photocatalytic activity. Recently, strategies have been reported to improve the performance of photocatalysts via doping, or the introduction of semiconductor heterojunctions by combining them with

• transition metals or with other semiconductors. Among them, semiconductor heterojunctions have attracted great attention [139]. The doping of TiO2 and ZnO NPs with the aim to conveniently tuning the bandgap energy values can be a suitable option. In this context, it has been verified for both types of NPs, a

• alternative interesting semiconductor–semiconductor heterojunctions. Finally, another approach to increase the photo-efficiency of the considered systems is the photosensitization of TiO2 and ZnO NPs to obtain visible-light responsive photocatalysts as well as solar-cell components [93][141][142]. These

Synthesis of novel C-doped g-C₃N₄ nanosheets coupled with CdIn₂S₄ for enhanced photocatalytic hydrogen evolution

• Jingshuai Chen,
• Chang-Jie Mao,
• Helin Niu and
• Ji-Ming Song

Beilstein J. Nanotechnol. 2019, 10, 912–921, doi:10.3762/bjnano.10.92

• photocatalytic activity of g-C3N4 is severely restricted by the inefficient separation of photogenerated electron–hole pairs and insufficient photon absorption. Up to now, a variety of strategies such as anion doping, novel metal deposition on surfaces and the design of heterojunctions/nanocomposites have been

Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• of semiconductor interfaces Reduced graphene oxide (rGO), which plays the role of a p-type semiconductor, can form heterojunctions when forming composites with most metal-oxide semiconductors. In the example of a SnO2–rGO sensor [45], SnO2 and rGO formed p–n heterojunctions. The enhancement mechanism

• , meaning that electrons transfer from rGO to SnO2 in the heterojunctions. The Schottky barrier is only 0.2 eV due to the changed Fermi level of the composite structure after achieving a dynamic balance of the electron flow, indicating that the electrons are able to pass through the energy barrier. In

• heterojunctions. However, p–n junctions cause the recombination of charge carriers with a decreased amount of charge carriers, while p–p junctions lead to spatially separated charge carriers with an unchanged amount of charge carriers. The following summarizes the parameters of several room-temperature gas

Thickness-dependent photoelectrochemical properties of a semitransparent Co₃O₄ photocathode

• Malkeshkumar Patel and
• Joondong Kim

Beilstein J. Nanotechnol. 2018, 9, 2432–2442, doi:10.3762/bjnano.9.228

• indicating the stoichiometric ratio of 1:2. We propose that a semitransparent Co3O4 photoactive electrode is a prospective candidate for use in PEC cells via heterojunctions for hydrogen generation. Keywords: cobalt(II,III) oxide (Co3O4); photocathode; photoelectrochemical cells; semitransparent; thickness

• heterojunctions. Experimental Sample fabrication: The photocathode was composed of Co3O4/fluorine-doped tin oxide (FTO)/glass. The general synthesis of Kirkendall diffusion grown Co3O4 film was analogue to our previous study [20]. In brief, a commercial fluorine-doped tin oxide (FTO)-coated glass (735167, Sigma

Hierarchical heterostructures of Bi₂MoO₆ microflowers decorated with Ag₂CO₃ nanoparticles for efficient visible-light-driven photocatalytic removal of toxic pollutants

• Shijie Li,
• Wei Jiang,
• Shiwei Hu,
• Yu Liu,
• Yanping Liu,
• Kaibing Xu and
• Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 2297–2305, doi:10.3762/bjnano.9.214

• obstacle, various methods have been developed, including doping [20][21] and the construction of heterojunctions [22][23][24][25][26][27][28][29][30][31][32][33]. Particularly, the combination of Bi2MoO6 with other semiconductors to construct heterojunction photocatalysts leads to an enhanced activity of

• photocatalytic activity [37]. However, it is unstable under illumination. Previous studies found that the good stability of Ag2CO3 could be achieved through the rational construction of heterojunctions, such as Ag2CO3/Bi2WO6 [37], Ag2O/Ag2CO3 [38], Ag2CO3/Bi2O2CO3 [39], Ag2CO3/C3N4 [40], Ag/Ag2CO3/BiVO4 [41

• another 2 h. The collected solid was washed, and dried at 70 °C overnight. By varying the added amounts of AgNO3, NaHCO3, and NH3·H2O, the as-prepared Ag2CO3/Bi2MoO6 heterojunctions with various weight ratios (0. 1/1, 0.2/1, 0.3/1 and 0.5/1) were obtained and denoted as ACO/BMO-10, ACO/BMO-20, ACO/BMO-30

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

A scanning probe microscopy study of nanostructured TiO₂/poly(3-hexylthiophene) hybrid heterojunctions for photovoltaic applications

• Laurie Letertre,
• Roland Roche,
• Olivier Douhéret,
• Hailu G. Kassa,
• Denis Mariolle,
• Nicolas Chevalier,
• Łukasz Borowik,
• Philippe Dumas,
• Benjamin Grévin,
• Roberto Lazzaroni and
• Philippe Leclère

Beilstein J. Nanotechnol. 2018, 9, 2087–2096, doi:10.3762/bjnano.9.197

• -UGA, 17 rue des Martyrs F-38054, Grenoble, France 10.3762/bjnano.9.197 Abstract The nanoscale morphology of photoactive hybrid heterojunctions plays a key role in the performances of hybrid solar cells. In this work, the heterojunctions consist of a nanocolumnar TiO2 surface covalently grafted with a

• theoretical and material design perspective. Keywords: hybrid heterojunctions; hybrid photovoltaic; Kelvin probe force microscopy; photoconductive-AFM; photo-KPFM; poly(3-hexylthiophene); TiO2; Introduction Over the past decades, a large range of photovoltaic (PV) technologies have been developed for the

• other hand. Hybrid PV devices include various technologies such as perovskite cells, dye sensitized solar cells (DSSC), with power efficiencies up to 13% [5] and hybrid bulk heterojunctions (HBHJ), which combine an organic matrix and inorganic semiconducting nanostructures such as quantum dots. Among

The role of the Ge mole fraction in improving the performance of a nanoscale junctionless tunneling FET: concept and scaling capability

• Hichem Ferhati,
• Fayçal Djeffal and
• Toufik Bentrcia

Beilstein J. Nanotechnol. 2018, 9, 1856–1862, doi:10.3762/bjnano.9.177

• , where the optimized design exhibits an improved switching behavior at the nanoscale level. These results make the optimized device suitable for designing digital circuit for high-performance nanoelectronic applications. Keywords: ambipolar conduction; heterojunctions; junctionless tunneling field

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• have been reported on photocatalytic reduction of Cr(VI) by TiO2–p-type semiconductor metal oxide heterojunctions. The mechanism for visible-light-driven photocatalytic reduction of Cr(VI) on TiO2–p-type metal oxide heterojunctions is explained in Figure 9. Cuprous oxide (Cu2O) is a p-type

Robust midgap states in band-inverted junctions under electric and magnetic fields

• Álvaro Díaz-Fernández,
• Natalia del Valle and
• Francisco Domínguez-Adame

Beilstein J. Nanotechnol. 2018, 9, 1405–1413, doi:10.3762/bjnano.9.133

• semiconductor. A salient feature is the existence of interface states lying within the gap, provided that the two gaps overlap [13][14][15][16][17]. These states are protected by symmetry, and are responsible for the conducting properties of the surface. In IV–VI heterojunctions, such as PbTe/SnTe, interface

• field is applied along the growth direction, parallel to the electric field, will also be briefly discussed for comparison. Theoretical model We consider heterojunctions of IV–VI compound semiconductors, such as Pb1−xSnxTe and Pb1−xSnxSe. The latter are known to shift from being semiconductors to

Ag₂WO₄ nanorods decorated with AgI nanoparticles: Novel and efficient visible-light-driven photocatalysts for the degradation of water pollutants

• Shijie Li,
• Shiwei Hu,
• Wei Jiang,
• Yanping Liu,
• Yu Liu,
• Yingtang Zhou,
• Liuye Mo and
• Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 1308–1316, doi:10.3762/bjnano.9.123

• , to enhance the photocatalytic performance of Ag2WO4, AgI (possessing matched energy band levels) was chosen as a suitable component to combine with Ag2WO4, AgI/Ag2WO4 heterojunctions at different mole ratios. These heterojunctions were prepared via an in situ ion-exchange approach, utilizing Ag2WO4

• nanorods as the Ag source. The as-prepared AgI/Ag2WO4 heterojunctions exhibited remarkably higher photocatalytic activity than pure Ag2WO4 toward the degradation of rhodamine B (RhB), methyl orange (MO) and para-chlorophenol (4-CP) under visible light. Based on a systematic characterization and study, a

• /Ag2WO4, and 0.4AgI/Ag2WO4, respectively. The XRD patterns of pure Ag2WO4, pure AgI, and AgI/Ag2WO4 heterojunctions are displayed in Figure 1. Pure Ag2WO4 is in its orthorhombic structure (JCPDS no. 70-1719) and exhibits several strong peaks at 30.3°, 31.8°, 33.1, 45.6°, 54.8° and 58.3°, which can be

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

• content x varies quite smoothly on the characteristic length of about 1 µm along the heterojunctions between the buffer and the film, as well as between the film and the cap layer. Previously, it was theoretically demonstrated that in such a situation, there should appear a 3D potential well in the