Fabrication of hafnium-based nanoparticles and nanostructures using picosecond laser ablation

• Abhishek Das,
• Mangababu Akkanaboina,
• Jagannath Rathod,
• R. Sai Prasad Goud,
• Kanaka Ravi Kumar,
• Raghu C. Reddy,
• Ratheesh Ravendran,
• Katia Vutova,
• S. V. S. Nageswara Rao and
• Venugopal Rao Soma

Beilstein J. Nanotechnol. 2024, 15, 1639–1653, doi:10.3762/bjnano.15.129

• /bjnano.15.129 Abstract This work presents a unique and straightforward method to synthesise hafnium oxide (HfO2) and hafnium carbide (HfC) nanoparticles (NPs) and to fabricate hafnium nanostructures (NSs) on a Hf surface. Ultrafast picosecond laser ablation of the Hf metal target was performed in three

• different liquid media, namely, deionised water (DW), toluene, and anisole, to fabricate HfO2 and HfC NPs along with Hf NSs. Spherical HfO2 NPs and nanofibres were formed when Hf was ablated in DW. Hf ablated in toluene and anisole demonstrated the formation of core–shell NPs of HfC with a graphitic shell

• formation of laser-induced periodic surface structures (LIPSS) with low spatial frequency (LSFL) and high spatial frequency (HSFL) orthogonal to each other was also demonstrated. The LSFL and HSFL both exhibited quasi-periodicity. This work presents a simple way to fabricate HfO2 and HfC NPs and provides

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

• ]. This structure uses two surrounding nanogap cavities separated by HfO2 as a high-k dielectric material and SiO2 as an interface layer. It has been reported that this structure offers higher sensitivity compared to that of the dual-material JL MOSFET-biosensor proposed by Ahangari et al. [74] and the

• was employed for the fabrication of the NW structure [92]. Moreover, this device is gated by a back gate and one or two platinum side gates via a liquid which has been characterized for possible implementation in reliable sensing applications. This biosensor uses HfO2 as a high-k gate dielectric

• include biomolecule species. This structure utilizes MoS2 in the body channel region and HfO2 as a high-k dielectric placed between the electrode gates and the body channel. It has been indicated that the sensitivity parameter of the designed biosensor is almost 100% higher in the case of the TMD FET

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

• to reduce gate oxide leakage are high-k materials. The device’s ability to keep a charge is increased by using high-k materials, which also aids in downsizing. HfO2 is compatible with a silicon substrate and possesses a high dielectric constant (ε ≈ 25), a large bandgap (5.68 eV), band offsets with

• low-work-function live strip (LWLS), has a work function compatible to that of HfO2 [19][20]. The combination of metal strip and high-k material at the drain yields values of Ioff = 1.40 × 10−17, Ion/Ioff ratio = 7.14 × 1011, a reduced subthreshold swing of 5 mV/dec, as well as lower ambipolarity and

Theoretical investigations of oxygen vacancy effects in nickel-doped zirconia from ab initio XANES spectroscopy at the oxygen K-edge

• Dick Hartmann Douma,
• Lodvert Tchibota Poaty,
• Alessio Lamperti,
• Stéphane Kenmoe,
• Abdulrafiu Tunde Raji,
• Alberto Debernardi and
• Bernard M’Passi-Mabiala

Beilstein J. Nanotechnol. 2022, 13, 975–985, doi:10.3762/bjnano.13.85

• initial system for the calculations consists of a tetragonal supercell of ZrO2 containing 96 atoms (64 O atoms and 32 Zr atoms), which eventually relaxes to an approximately cubic supercell as an effect of doping (see [4][40][41] for Fe-doped ZrO2 and [42] for Ge-doped HfO2, a similar oxide, where a

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

• a much wider (several hundred nanometers) semiconducting (e.g., doped or nonstoichiometric oxide) layer. Materials used either for insulating or semiconducting layers include HfO2 [3][15][16][17][18], ZnO [19][20], CuO [21][22][23][24][25][26][27], ZrO2 [12], Ta2O5 [28][29], and NiO [3][30][31][32

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• the removal of the native oxide layer followed by an adequate surface passivation technique [13] and/or by a proper choice of the dielectric and its deposition method. Regarding the dielectric, the most common ones are aluminum oxide (Al2O3) and hafnium dioxide (HfO2) for which the preferable

Synthesis of hafnium nanoparticles and hafnium nanoparticle films by gas condensation and energetic deposition

• Irini Michelakaki,
• Nikos Boukos,
• Dimitrios A. Dragatogiannis,
• Spyros Stathopoulos,
• Costas A. Charitidis and
• Dimitris Tsoukalas

Beilstein J. Nanotechnol. 2018, 9, 1868–1880, doi:10.3762/bjnano.9.179

• hexagonal biprism shape and are prone to surface oxidation when exposed to ambient air forming core–shell Hf/HfO2 structures. Hafnium nanoparticle thin films were formed through energetic nanoparticle deposition. This technique allows for the control of the energy of charged nanoparticles during vacuum

• constant HfO2 and its compounds are used in the field of microelectronics for the manufacturing of integrated circuits and more particularly as gate dielectrics of metal-oxide semiconductor transistors having replaced the traditional thermally grown SiO2 dielectric [34]. More recently, HfO2 was also

• corresponding to the (10−10) crystal planes of hexagonal close-packed (hcp) Hf (Figure 2, regions A, JCPDS 00-038-1478). In the shell, the coexistence of nanocrystallites of orthorhombic HfO2 (Figure 2, regions with arrows) within amorphous regions is observed. The distance between adjacent planes in the shell

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

• describes schematically the investigated DG-HJ-JL TFET structure. The cornerstone of the proposed design is the assumption of a uniformly and highly doped heterochannel (Si1−xGex/Si/Ge), which can be indicated by n+/n+/n+. In addition, the proposed design is suggested with a HfO2 gate dielectric in order to

Atomic layer deposition and properties of ZrO₂/Fe₂O₃ thin films

• Kristjan Kalam,
• Helina Seemen,
• Peeter Ritslaid,
• Mihkel Rähn,
• Aile Tamm,
• Kaupo Kukli,
• Aarne Kasikov,
• Joosep Link,
• Raivo Stern,
• Salvador Dueñas,
• Helena Castán and
• Héctor García

Beilstein J. Nanotechnol. 2018, 9, 119–128, doi:10.3762/bjnano.9.14

• [11]. Phase diagrams for the ZrO2–FeO system were described [12] and the influence of thermal treatment on the phase development in ZrO2–Fe2O3 and HfO2–Fe2O3 systems was assessed [13]. ALD of ZrO2 from ZrCl4 and O3 has been studied [14]. Reactions between Fe(acac)3 adsorbing on zirconia surfaces [15

• thickness as a function of growth per cycle was also observed with HfO2 [28] and ZrO2 [29]. The growth rate for a single deposition was different for each sample in the reactor because of the reactor type and positioning of the samples (Figure 1). The growth rate decreased with increasing distance between

• -centrosymmetric orthorhombic phase of HfO2 stabilized by doping with foreign cations [40], well-defined ferroelectric hysteresis was recorded. For stabilized hafnia [40] the electrical polarization charge clearly tended to saturate upon the incremental increase in the external electric field strength. Along with

Advances in the fabrication of graphene transistors on flexible substrates

• Gabriele Fisichella,
• Stella Lo Verso,
• Silvestra Di Marco,
• Vincenzo Vinciguerra,
• Emanuela Schilirò,
• Salvatore Di Franco,
• Raffaella Lo Nigro,
• Fabrizio Roccaforte,
• Amaia Zurutuza,
• Alba Centeno,
• Sebastiano Ravesi and
• Filippo Giannazzo

Beilstein J. Nanotechnol. 2017, 8, 467–474, doi:10.3762/bjnano.8.50

• applications. In this case the thickness and the dielectric constant of the insulating film have crucial importance in order to maintain a reasonably high gate capacitance of the final device. In particular, considering high κ-dielectrics such as HfO2 or Al2O3 with film thickness in the order of 10 nm, the

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

• be fully described only through Ge-nps size. Ge-nps embedded in different dielectric matrices (e.g., SiO2, Si3N4 or HfO2) have been already used for fabrication of high-efficiency photodetectors [15], multilayer memory devices [16] and other applications as solar photoconversion cells [17], batteries

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• , Puiestee 78, 51008 Tartu, Estonia, IMEP-LAHC, CNRS, Université de Grenoble-Alpes, Minatec campus, 38016 Grenoble, France 10.3762/bjnano.7.101 Abstract A hybrid material consisting of nonfunctionalized multiwall carbon nanotubes (MWCNTs) and cubic-phase HfO2 nanoparticles (NPs) with an average diameter of

• 2.6 nm has been synthesized. Free standing HfO2 NPs present unusual optical properties and a strong photoluminescence emission in the visible region, originating from surface defects. Transmission electron microscopy studies show that these NPs decorate the MWCNTs on topological defect sites. The

• electronic structure of the C K-edge in the nanocomposites was probed by electron energy loss spectroscopy, highlighting the key role of the MWCNT growth defects in anchoring HfO2 NPs. A combined optical emission and absorption spectroscopy approach illustrated that, in contrast to HfO2 NPs, the metallic

Electrical contacts to individual SWCNTs: A review

• Wei Liu,
• Christofer Hierold and
• Miroslav Haluska

Beilstein J. Nanotechnol. 2014, 5, 2202–2215, doi:10.3762/bjnano.5.229

• investigated. In particular, the organic contamination and gold etching issues must be examined. Park et al. [88] presented another wafer-level scalable process to disperse SWCNTs onto the pre-patterned substrate. A high density of SWCNTs were selectively deposited onto an array of HfO2 trenches by using an

Numerical investigation of the effect of substrate surface roughness on the performance of zigzag graphene nanoribbon field effect transistors symmetrically doped with BN

• Majid Sanaeepur,
• Arash Yazdanpanah Goharrizi and
• Mohammad Javad Sharifi

Beilstein J. Nanotechnol. 2014, 5, 1569–1574, doi:10.3762/bjnano.5.168

• as function of the energy for various SR correlation lengths (δSR = 200 pm). The inset shows the transport gap versus SR correlation length. Schematic representation of the simulated device structure. The gate insulator is assumed to be 2.5 nm thick HfO2 (κ = 25). Source and drain contacts are

Growth and characterization of CNT–TiO₂ heterostructures

• Yucheng Zhang,
• Ivo Utke,
• Johann Michler,
• Gabriele Ilari,
• Marta D. Rossell and
• Rolf Erni

Beilstein J. Nanotechnol. 2014, 5, 946–955, doi:10.3762/bjnano.5.108

• , e.g., trimethylaluminium for Al2O3, titanium tetraisopropoxide for TiO2, diethylzinc for ZnO, or tetrakis(ethylmethylamido)hafnium for HfO2, need surfaces that are terminated with a functional group, which would allow for their dissociative chemisorption reaction. Hydroxy-(OH)-group terminated

Quantum size effects in TiO₂ thin films grown by atomic layer deposition

• Massimo Tallarida,
• Chittaranjan Das and
• Dieter Schmeisser

Beilstein J. Nanotechnol. 2014, 5, 77–82, doi:10.3762/bjnano.5.7

• subtraction procedure is validated by the fact that in a previous experiment [26], in which we deposited HfO2 on SiO2 and characterized with XAS cycle by cycle, we could observe that the O-K XAS of SiO2 does not change during the deposition of HfO2. From the difference spectra the different intensity of peak

Characterization of electroforming-free titanium dioxide memristors

• John Paul Strachan,
• J. Joshua Yang,
• L. A. Montoro,
• C. A. Ospina,
• A. J. Ramirez,
• A. L. D. Kilcoyne,
• Gilberto Medeiros-Ribeiro and
• R. Stanley Williams

Beilstein J. Nanotechnol. 2013, 4, 467–473, doi:10.3762/bjnano.4.55

• HfO2 [18][19][20][21][22][23][24]. Recently, physical characterization of Pt/TiO2/Pt unipolar [25] and bipolar [26] resistance-switching devices by TEM and X-ray absorption revealed that the switching involves the creation of localized channels of Ti4O7 within the matrix material. The Ti4O7 channel