Marco Fanciulli

Università degli Studi di Milano-Bicocca | UNIMIB · Department of Materials Science

Half-metallic half-Heusler compounds with strong spin-orbit-coupling and broken inversion symmetry in their crystal structure are promising materials for generating and absorbing spin-currents, thus enabling the electric manipulation of magnetization in energy-efficient spintronic devices. In this work, we report the spin-to-charge conversion in sp...

Properly tuning the Fermi level position in topological insulators is of vital importance to tailor their spin-polarized electronic transport and to improve the efficiency of any functional device based on them. Here we report the full in situ Metal Organic Chemical Vapor Deposition (MOCVD) and study of a highly crystalline Bi2Te3/Sb2Te3 topologica...

Large-area antimony telluride (Sb2Te3) thin films are grown by a metal organic chemical vapor deposition technique on 4” Si(111) substrates, and their topological character probed by magnetoconductance measurements. When interfaced with Fe thin films, broadband ferromagnetic resonance spectroscopy (BFMR) shows a clear increase of the damping parame...

Spin‐charge interconversion phenomena at the interface between magnetic materials and topological insulators (TIs) are attracting enormous interest in the research effort toward the development of fast and ultra‐low power devices for future information and communication technology. A large spin‐to‐charge (S2C) conversion efficiency in Au/Co/Au/Sb2T...

!!!Now available at Advanced Functional Materials https://onlinelibrary.wiley.com/doi/10.1002/adfm.202109361!!! Spin-charge interconversion phenomena at the interface between magnetic materials and topological insulators (TIs) are attracting enormous interest in the research effort towards the development of fast and ultra-low power devices for th...

The main feature of amorphous materials is the presence of excess vibrational modes at low energies, giving rise to the so-called “boson peak” in neutron and optical spectroscopies. These same modes manifest themselves as two-level systems (TLSs) causing noise and decoherence in qubits and other sensitive devices. Here, we present an experiment tha...

When coupled with ferromagnetic layers (FM), topological insulators (TI) are expected to boost the charge‐to‐spin conversion efficiency across the FM/TI interface. In this context, a thorough control and optimization of the FM/TI interface quality are requested. Here, the evolution of the chemical, structural, and magnetic properties of the Fe/Sb2T...

We report here the synthesis of undoped and Cu-doped Cs2ZnCl4 nanocrystals (NCs), in which we could tune the concentration of Cu from 0.7% to 7.5%. Cs2ZnCl4 has a wide band gap (4.8eV) and its crystal structure is composed of isolated ZnCl4 tetrahedra surrounded by Cs+ cations. According to our electron paramagnetic resonance analysis, in 0.7% and...

We report here the synthesis of undoped and Cu-doped Cs₂ZnCl₄ nanocrystals (NCs), in which we could tune the concentration of Cu from 0.7% to 7.5%. According to electron paramagnetic resonance analysis, in 0.7% and 2.1% Cu-doped NCs the Cu ions were present in the +1 oxidation state only, while in NCs at higher Cu concentratio...

Taking the full advantage of the conformal growth characterizing atomic layer deposition (ALD), the possibility to grow Co thin films, with thickness from several tens down to few nanometers on top of a granular topological insulator (TI) Sb2Te3 film, exhibiting a quite high surface roughness (2–5 nm), was demonstrated. To study the Co growth on th...

Several spin qubit architectures have been proposed, theoretically investigated and realized at least on the scale of single devices in view of quantum computation and simulation applications. We focus our study on five qubit types: quantum dot spin qubit, double quantum dot singlet-triplet qubit, double quantum dot hybrid qubit, donor qubit, quant...

Transition metal dichalcogenides (TMDCs) ultrathin layers have attracted considerable interest in the recent years. Their peculiar functional properties can be exploited in electronics, spintronics, optoelectronics, photonics, energy production, harvesting and storage. The availability of cost-effective, green, and efficient growth processes is of...

Inversion recovery with electron spin-echo detection has been used to study the electron spin-lattice relaxation rates 1/T1 for transition metal impurities in heavily cobalt-doped hydrothermally grown ZnO single crystals. The relaxation dynamics of Co2+ ions dominates the phonon bottleneck effect in the Orbach-Aminov process, which involves the mod...

We study theoretically the phonon-induced relaxation and decoherence processes in the hybrid qubit in silicon. A hybrid qubit behaves as a charge qubit when the detuning is close to zero and as a spin qubit for large detuning values. It is realized starting from an electrostatically defined double quantum dot where three electrons are confined and...

At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore’s law is approaching the insurmountable barrier given by the ultimate atomic nature of matter. A major challenge for 21st century scientists is finding novel strategies, concepts an...

We study theoretically the phonon-induced relaxation and decoherence processes in the hybrid qubit in silicon. Hybrid qubit behaves as a charge qubit when the detuning is close to zero and as spin qubit for large detuning values. It is realized starting from an electrostatically defined double quantum dot where three electrons are confined and mani...

The main feature of amorphous materials is the presence of excess vibrational modes at low energies, giving rise to the so called "boson peak" in neutron and optical spectroscopy. These same modes manifest themselves as two level systems (TLSs) causing noise and decoherence in qubits and other sensitive devices. Here we present an experiment that u...

Control of magnetic domain-wall motion in nanowires has attracted great interest due to the possibility to develop nonvolatile memory and logic circuits. We show that efficient domain-wall pinning can be engineered by growing Co−Fe−B/MgO ultra-thin magnetic films with perpendicular anisotropy on a patterned substrate exhibiting subnanometer steps m...

Interfacing Topological Insulators (TI) with ferromagnetic (FM) layers is a promising route towards the next generation of ultra-low power spintronic devices based on charge-to-spin current conversion. Here, we present the Fe/Sb2Te3 interface structure, chemical composition and magnetic properties. Thin films (30 nm) of the topological insulator Sb...

Halide perovskite nanocrystals hold promise for printable optoelectronic and photonic applications. Doping enhances their functionalities and is being investigated for substituting lead with environmentally friendlier elements. The most investigated dopant is Mn2+ that acts as a color center sensitized by the host excitons. The sensitization mechan...

A comparison of gate fidelities between different spin qubit types defined in quantum dots and a donor under different control errors is reported. We studied five qubit types, namely the quantum dot spin qubit, the double quantum dot singlet-triplet qubit, the double quantum dot hybrid qubit, the donor qubit and the quantum dot spin-donor qubit. Fo...

We investigated the Phase Change Memory (PCM) capabilities of In-doped Sb nanowires (NWs) with diameters of (20-40) nm, which were self-assembled by Metalorganic Chemical Vapor Deposition (MOCVD) via the vapor-liquid-solid (VLS) mechanism. The PCM behavior of the NWs was proved, and it was shown to have relatively low reset power consumption (~ 400...

The unavoidable effect of the environmental noise due to nuclear spins and charge traps is included in the study of the hybrid qubit dynamics. Hybrid qubit owes its name to the advantageous combination of manipulation speed of a charge qubit with the longevity of a spin qubit. It consists of three electrons confined through external gate voltages i...

We show here the first colloidal synthesis of double perovskite Cs2AgInCl6 nanocrystals (NCs) with a control over their size distribution. In our approach, metal carboxylate precursors and ligands (oleylamine and oleic acid) are dissolved in diphenyl ether and reacted at 105°C with benzoyl chloride. The resulting Cs2AgInCl6 NCs exhibit the expected...

A comparison of gate fidelities between different spin qubit types defined in quantum dots and donor under different control errors is reported. We studied five qubit types, namely the quantum dot spin qubit, the double quantum dot singlet-triplet qubit, the double quantum dot hybrid qubit, the donor qubit and the quantum dot spin-donor qubit. For...

The unavoidable effect of the environmental noise due to nuclear spins and charge traps is included in the study of the hybrid qubit dynamics. Hybrid qubit dues its name to the advantageous combination of manipulation speed of a charge qubit with the longevity of a spin qubit. It consists of three electrons confined through external gate voltages i...

The effects of magnetic and charge noises on the dynamical evolution of the double-dot exchange-only qubit (DEOQ) is theoretically investigated. The DEOQ consisting of three electrons arranged in an electrostatically defined double quantum dot deserves special interest in quantum computation applications due to its advantages in terms of fabricatio...

The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of ⁵⁷Fe emission Mössbauer spectroscopy, following dilute implantation of ⁵⁷Mn (T1/2 = 1.5 min) at ISOLDE/CERN, to study the electronic charge...

Explicit controlled-NOT gate sequences between two qubits of different types are presented in view of applications for large-scale quantum computation. Here, the building blocks for such composite systems are qubits based on the electrostatically confined electronic spin in semiconductor quantum dots. For each system the effective Hamiltonian model...

Resistive random access memories (RRAM) are one of the main constituents of the class of memristive technologies that are today considered very promising in semiconductor industry because of their high potential for several applications ranging from non-volatile memories to neuromorphic hardware. The latter application is particularly interesting,...

Control of electron spin coherence via external fields is fundamental in spintronics. Its implementation demands a host material that accommodates the desirable but contrasting requirements of spin robustness against relaxation mechanisms and sizeable coupling between spin and orbital motion of the carriers. Here, we focus on Ge, which is a promine...

Supplementary Figures 1-4, Supplementary Notes 1-6 and Supplementary References.

The thermal resistance along the thickness of In3SbTe2 crystalline nanowires was measured using the scanning thermal microscopy in 3ω mode. The nanowires were grown by metal organic vapor deposition, exploiting the VLS mechanism induced by Au metal-catalyst nanoparticles and harvested on a SiO2/Si substrate. Two nanowires with different thickness (...

We report on the fabrication and electrical characterization of phase change memory (PCM) devices formed by In3Sb1Te2 chalcogenide nanowires (NWs), with diameters as small as 20 nm. The NWs were self-assembled by metal organic chemical vapor deposition via the vapor–liquid–solid method, catalyzed by Au nanoparticles. Reversible and well reproducibl...

Emerging brain-inspired architectures call for devices that can emulate the functionality of biological synapses in order to implement new efficient computational schemes able to solve ill-posed problems. Various devices and solutions are still under investigation and, in this respect, a challenge is opened to the researchers in the field. Indeed,...

The resistance switching dynamics of TiN/HfO2/Pt devices is analyzed in this paper. When biased with a voltage ramp of appropriate polarity, the devices experience SET transitions from high to low resistance states in an abrupt manner, which allows identifying a threshold voltage. However, we find that the stimulation with trains of identical pulse...

In the present work we focus on the investigation by electron spin resonance (EPR) and complementary techniques (such as SEM, ToF-SIMS, XPS) of silicon nanowires produced by metal-assisted chemical etching (MACE). In particular we will report on the impact of the MACE process on the donors (P and As) and on surface passivation processes based on H...

In this work, the fabrication, the electrical and optical characterization of red organic light emitting transistors using thin film made of alumina grown by atomic layer deposition (ALD) coupled with PMMA (poly(methyl methacrylate)) as gate dielectric material are reported. Use of ALD-grown Al2O3 is shown to greatly reduce the operation range and...

The investigation of mechanical properties of atomic layer deposition HfO2 films is important for implementing these layers in microdevices. The mechanical properties of films change as a function of composition and structure, which accordingly vary with deposition temperature and post-annealing. This work describes elastic modulus, hardness, and w...

The growth of atomically thin MoS2 films is achieved by sulfurization of molybdenum oxide precursor films grown by atomic layer deposition. The quality features of the MoS2 films are engineered controlling the stoichiometry, morphology, and thickness of the precursors. The interface interaction between the precursor films and the substrates (SiO2 o...

We report on the development of a modular system of high-frequency printed circuit boards (PCBs) for electrical low-noise characterization of multigate quantum devices. The whole measurement setup comprises PCBs operating from room temperature to a few kelvins, and custom software to control the broadband electronics held at cryogenic and room temp...

Scalability from single qubit operations to multi-qubit circuits for quantum information processing requires architecture-specific implementations. Semiconductor hybrid qubit architecture is a suitable candidate to realize large scale quantum information processing, as it combines a universal set of logic gates with fast and all-electrical manipula...

No abstract is available for this article.

Nanoscale dielectric films made of alumina grown by atomic layer deposition (ALD) have been implemented as high-k dielectric material in organic light emitting transistors (OLETs). This leads to the reduction of both the threshold and operating bias regime of the devices while obtaining comparable light emission, when compared to our standard polym...

Control of electron spin coherence via external fields is fundamental in spintronics. Its implementation demands a host material that accommodates the highly desirable but contrasting requirements of spin robustness to relaxation mechanisms and sizeable coupling between spin and orbital motion of charge carriers. Here we focus on Ge, which, by matc...

Hexagonal orthoferrite h-ErFeO3 thin films are synthesized by Atomic Layer Deposition on SiO2(100 nm)/Si substrate, followed by rapid thermal annealing at 650–700 °C. Structural, chemical and morphological characterizations of as-deposited and annealed layers are performed by X-ray Reflectivity/Diffraction and Time-of-Flight Secondary Ion-Mass Spec...

The electronic band line-up between a uniform 2D silicon layer and a MoS2 substrate is shown to result in a distortion of the MoS2 bands. This effect is reflected in the admittance and electrical transport responses measured from the field-effect transistor incorporating the Si/MoS2 heterosheet interface and fabricated from MoS2 multilayer flakes o...

We report on the fabrication and the characterization of a tunable complementary-metal oxide semiconductor (CMOS) system consisting of two quantum dots and a MOS single electron transistor (MOSSET) charge sensor. By exploiting a compact T-shaped design and few gates fabricated by electron beam lithography, the MOSSET senses the charge state of eith...

The current status of the investigation of defects in silicon nanowires and at the interface between Si and its oxide in 1D nanostructures is reviewed and discussed. The paper concentrates on nanowires produced by metal assisted chemical etching. The role of defects at the interface between the semiconductor and its oxide and of hydrogen in passiva...

The recent discovery that magnetic domain walls can be moved under a small current without any magnetic field opens a perspective for a paradigm shift in mass storage design. However, several fundamental questions must be answered before the technology can be considered feasible. This review covers the current understanding of domain wall (DW) prop...

We report on the ground- and excited-state properties of Fe3+ centers in hydrothermally and chemical-vapor-transport grown single ZnO crystals studied by continuous-wave electron-paramagnetic resonance (EPR) under dark and laser-illuminated conditions, pulsed-EPR and magneto-photoluminescence. By use of EPR experiments, the fine-structure parameter...

The switching dynamics of filamentary Pt/HfO 2 /TiN memristive devices is managed through sub-threshold pulses in order to display gradual resistance decrease useful for analog logic computation based on spiking networks. Such memristive devices are known to display abrupt set transitions (resistance decrease) that require current limitation becaus...

Metal-assisted chemical etching (MACE) has gained great interest for the preparation of vertically aligned silicon nanowires (SiNWs); however, the process mechanism has not yet been identified. In this study, the influence of doping elements on the formation rate of SiNWs prepared by silver-assisted chemical etching was investigated. Two n-type sil...

The current status of the investigation of defects in silicon and germanium nanowires and at the interface between the group IV semiconductor and its oxide in 1D nanostructures is reviewed and discussed. The paper concentrates on nanowires produced by metal assisted chemical etching for silicon and by the vapor-liquid-solid (VLS) growth method for...

In this work, the self-assembly of In3Sb1Te2 and In-doped Sb4Te1 nanowires (NWs) for phase change memories application was achieved by metal organic chemical vapor deposition, coupled with vapor–liquid–solid (VLS) mechanism, catalyzed by Au nanoparticles. Single crystal In3Sb1Te2 and In-doped Sb4Te1 NWs were obtained for different reactor pressures...

Sb2Te3 is a chalcogenide compound of great interest, due to its applications in the fields of phase change, thermoelectric devices, as well as of topological insulators. In this work, the MOCVD deposition of both Sb2Te3 thin films and nanowires was performed by using the same set of precursors and exploiting the low temperature deposition for thin...

Sb2Te3 is a chalcogenide compound of great interest, due to its applications in the fields of phase change, thermoelectric devices, as well as of topological insulators. In this work, the MOCVD deposition of both Sb2Te3 thin films and nanowires was performed by using the same set of precursors and exploiting the low temperature deposition for thin...

Silicene grown on Ag(1 1 1) is characterized by several critical parameters. Among them, the substrate temperature plays a key role in determining the morphology during growth. However, an unexpected important role is also equally played by the post-deposition annealing temperature which determines the self-organization of silicene domains even in...

Resistive switching devices were at first conceived to be used in memory applications. Recently, they have also been studied as artificial synapses for neuromorphic applications. Therefore, lots of efforts are currently devoted to optimise both materials and programming techniques to design a device able to emulate the behavior of biological synaps...

Due to the confinement effect, the donor wave functions in nanostructures are highly localized on the defect and can even be deformed by the local geometry of the system. This can have relevant consequences on the hyperfine structure of the defect that can be exploited for advanced electronic applications. In this work we employ ab initio density f...

Free-standing silicene, a silicon analogue of graphene, has a buckled honeycomb lattice and, because of its Dirac bandstructure combined with its sensitive surface, offers the potential for a widely tunable two-dimensional monolayer, where external fields and interface interactions can be exploited to influence fundamental properties such as bandga...

In search for dilute magnetic semiconductors, the magnetic properties at the atomic-scale of Fe atoms incorporated in ZnO, in a concentration range of more than fi ve orders of magnitude from 1 × 10 −5 to 2.2 at% have been probed using emission 57 Fe Mössbauer spectroscopy on implanted 57 Mn and 57 Co produced at ISOLDE/CERN. In the ultra-dilute re...