Literatura científica selecionada sobre o tema "Platinum diselenide (PtSe₂)"

Exploiting the layer-dependent semiconductor-to-semimetal transition property, a PtSe₂ device with homogeneous coplanar structure demonstrate high mobility and extremely low contact resistance.

After the discovery of graphene in 2004, two-dimensional materials have attracted attention at large scale because of their peculiar structure and extraordinary properties. As they have large potential in future nano electronics, two-dimensional transition metal dichalcogenides has become most focus topic of study. Transition metal dichalcogenides with tunable finite band gap and significant transitional behavior are much suitable for the construction of electronic and optoelectronic devices of high-performance. However, platinum diselenide is group-10 transition metal dichalcogenides which occur naturally in one phase transition, which has been theoretically predicted as an excellent material. The proposed structure of surface plasmon resonance (SPR) -based biosensor consists of a silicon and two-dimensional nanomaterial platinum diselenide. The performance parameters of proposed biosensor (surface plasmon resonance-based) such as detection accuracy, figure of merit, sensitivity, full width at half maximum have been investigated. The sensitivity, detection accuracy, full width half maximum and figure of merit of proposed surface plasmon resonance biosensor having silver (50 nm), silicon (2 nm) and one layer of platinum diselenide with 2 nm thickness at 633 nm wavelength is 2200RIU–1 , 0.20 deg–1, 4.980 and 44.22 RIU–1 respectively. Silicon sheet is used in the middle of the Ag and platinum diselenide to prevent the oxidation of silver and enhance the sensitivity of platinum diselenide based surface plasmon resonance biosensor. The sensitivity of conventional surface plasmon resonance biosensor and the proposed surface plasmon resonance biosensor without silicon layer is 1700RIU–1 and 2000RIU–1 respectively. Surface plasmon resonance biosensor of device structure CaF2/Ag/Si/PtSe2 has higher sensitivity in comparison to device structures CaF2/Ag (conventional) and CaF2/Ag/PtSe2 (without Silicon Layer) by 29.41% and 10% respectively. Although the highest sensitivity obtained is 2620RIU–1 for 60 nm silver with 3 nm silicon layer except the platinum diselenide layer.

Platinum diselenide (PtSe2), which belongs to the transition metals dichalcogenide (TMDCs) class of 2D materials, is characterized with a transition from semimetal to semiconductor with a thickness variation from bulk to monolayer and found in versatile applications especially in sensors and mid-infrared detectors. In this study we report the large-scale synthesis of PtSe2 layers by thermally assisted selenization of pre-deposited platinum films in a horizontal quartz-tube Chemical Vapor Deposition (CVD) reactor. Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for characterization of the obtained 2D PtSe2. It is observed that the Raman spectra of PtSe2 show strong dependence on the thickness (Pt deposition time). XPS analysis was applied to examine the chemical compositions in order to assess the quality of the synthesized PtSe2 films. All the studied properties reveal great potential to obtain continuous layers with a controlled thickness and composition and further potential for integration in functional heterostructures for future nanoelectronic and optoelectronic devices.

We study the magnetic properties of platinum diselenide (PtSe2) intercalated with Ti, V, Cr, and Mn, using first-principle density functional theory (DFT) calculations and Monte Carlo (MC) simulations. First, we present the equilibrium position of intercalants in PtSe2 obtained from the DFT calculations. Next, we present the magnetic groundstates for each of the intercalants in PtSe2 along with their critical temperature. We show that Ti intercalants result in an in-plane AFM and out-of-plane FM groundstate, whereas Mn intercalant results in in-plane FM and out-of-plane AFM. V intercalants result in an FM groundstate both in the in-plane and the out-of-plane direction, whereas Cr results in an AFM groundstate both in the in-plane and the out-of-plane direction. We find a critical temperature of <0.01 K, 111 K, 133 K, and 68 K for Ti, V, Cr, and Mn intercalants at a 7.5% intercalation, respectively. In the presence of Pt vacancies, we obtain critical temperatures of 63 K, 32 K, 221 K, and 45 K for Ti, V, Cr, and Mn-intercalated PtSe2, respectively. We show that Pt vacancies can change the magnetic groundstate as well as the critical temperature of intercalated PtSe2, suggesting that the magnetic groundstate in intercalated PtSe2 can be controlled via defect engineering.

The extraordinary optoelectronic properties of platinum diselenide (PtSe2), whose structure is similar to graphene and phosphorene, has attracted great attention in new rapidly developed two-dimensional (2D) materials beyond the other 2D material family members. We have investigated the surface plasmon resonance (SPR) sensors through PtSe2 with the transfer matrix method. The simulation results show that the anticipated PtSe2 biochemical sensors have the ability to detect analytic. It is evident that only the sensitivities of Ag or Au film biochemical sensors were observed at 118°/RIU (refractive index unit) and 130°/RIU, whereas the sensitivities of the PtSe2-based biochemical sensors reached as high as 162°/RIU (Ag film) and 165°/RIU (Au film). The diverse biosensor sensitivities with PtSe2 suggest that this kind of 2D material can adapt SPR sensor properties.

We report the characterization of back-gated field-effect transistors fabricated using platinum diselenide () ultrathin films as a channel. We perform a detailed study of the electrical conduction as well as of the photoconductivity. From the gate modulation of the channel current, we obtain the signature of p-type semiconducting conduction with carrier mobility of about 30 cm2 V−1 s−1. More interestingly, devices exposed to light, either in air and in vacuum, exhibit negative photoconductivity, which we explain by a photogating effect due to charge trapping in the gate dielectric and light-induced desorption of adsorbates.

Le PtSe₂ est un matériau 2D de la famille des dichalcogénures de métaux de transition (TMDs) qui présente des propriétés intrinsèques exceptionnelles : mobilité des porteurs de charge élevée (200 - 450 cm².(V.s)⁻¹), gap électronique ajustable en fonction du nombre de monocouches (MLs), absorption optique large bande et excellente stabilité à l'air. Ces propriétés sont idéales pour des applications (opto)électroniques. Cependant, la croissance de PtSe₂ de haute qualité cristalline sur un substrat à bas coût et isolant reste un enjeu majeur. Ici, la synthèse de PtSe₂ bicouche à multicouche (< 20 MLs) par épitaxie par jets moléculaires (MBE) est optimisée sur un substrat de saphir. Les caractérisations systématiques comprennent la diffraction électronique (RHEED), la spectroscopie Raman, la spectroscopie de rayons X à dispersion d'énergie (EDS) et des mesures électriques de conductivité. Pour les films épais de PtSe₂ semi-métallique, on démontre que des températures élevées de croissance (520 °C) et de recuit (690 °C), ainsi qu'un fort flux de sélénium (Ф(Se) = 0,5 Å.s⁻¹ ; Ф(Se)/Ф(Pt) ~ 170), permettent d'obtenir une haute qualité cristalline et une haute conductivité électrique. L'impact du recuit post-croissance sur les propriétés structurelles des films épais est particulièrement étudié par diffraction des rayons X (XRD) et microscopie électronique à transmission (STEM). Les films de PtSe₂ non recuits consistent en une distribution 3D de domaines superposés ayant différentes orientations dans le plan, tandis que les films recuits consistent en un réseau 2D de domaines monocristallins selon l'axe c. En d'autres termes, les films non recuits ont des domaines d'épaisseur plus faible que celle du film et sont constitués de phases semi-conductrices et semi-métalliques, entraînant une faible conductivité (0,5 mS). Au contraire, les films recuits sont composés uniquement de domaines quasi-monocristallins et semi-métalliques, et présentent une très haute conductivité, jusqu'à 1,6 mS. On montre également que l'indicateur de qualité cristalline couramment utilisé, qui est la largeur à mi-hauteur (FWHM) du pic Raman Eg, n'est valide que s'il est étudié conjointement avec la FWHM du pic Raman A1g. On démontre que plus la FWHM des pics Eg et A1g est faible, plus la qualité cristalline des films de PtSe₂ dans le plan et hors du plan, respectivement, est élevée, et plus la conductivité électrique augmente. Concernant les films bicouches de PtSe₂ semi-conducteur, on obtient des films de haute qualité cristalline, dont la FWHM des pics Eg et A1g est comparable à celle des cristaux exfoliés, en effectuant une synthèse avec un flux périodique de Pt (periodic supply epitaxy). Les films de PtSe₂ bicouches à multicouches ne sont pas monocristallins mais présentent une texture de fibre selon l'axe c, ce qui est typique sur un substrat de saphir. On démontre pour la première fois l'épitaxie d'un film épais de PtSe₂ sur des surfaces vicinales (marches) de saphir. Pour finir, nous avons fabriqué des dispositifs optoélectroniques fonctionnant à 1,55 µm, la longueur d'onde typique des télécommunications par fibre optique. Ils sont à base de PtSe₂ épais semi-métallique, présentant une haute conductivité électrique et une bonne absorption optique à 1,55 µm, qui est directement synthétisé sur un substrat de saphir 2 pouces. On montre des photodétecteurs à base de PtSe₂ avec une largeur de bande record de 60 GHz et le premier mélangeur optoélectronique à base d'un TMD présentant, de plus, une largeur de bande supérieure à 30 GHz
PtSe₂ is a 2D material from the transition metal dichalcogenide (TMD) family that exhibits outstanding intrinsic properties: high charge carrier mobility (200 - 450 cm².(V.s)⁻¹), tunable bandgap with the number of monolayers (MLs), broadband optical absorption and excellent air stability. These properties are ideally suited for (opto)electronic applications. However, the growth of high crystalline quality PtSe₂ on low-cost and insulating substrates remains a major challenge. Here, the synthesis of bilayer to multilayer PtSe₂ films (< 20 MLs) by molecular beam epitaxy (MBE) is optimized on a sapphire substrate. The systematic characterizations include electron diffraction (RHEED), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX) and electrical conductivity measurements. For thick semimetallic PtSe₂ films, we demonstrate that high growth (520°C) and annealing (690°C) temperatures, combined with a high selenium flux (Ф(Se) = 0.5 Å.s⁻¹; Ф(Se)/Ф(Pt) ~ 170), leads to high crystalline quality and high electrical conductivity. In particular, the effect of the post-growth annealing on the structural properties of the thick films is investigated using X-ray diffraction (XRD) and transmission electron microscopy (STEM). We show that non-annealed PtSe₂ films consist of a 3D random distribution of superimposed domains with different in-plane orientations, while the annealed films consist of a 2D network of single-crystalline domains along the c-axis. In other words, non-annealed films have domains with a thickness smaller than that of the film and are composed of both semiconducting and semimetallic phases, resulting in low electrical conductivity (0.5 mS). In contrast, the annealed films are composed solely of quasi-single-crystalline and semimetallic domains, and exhibit high conductivity, up to 1.6 mS. We also show that the commonly used crystalline quality indicator, which is the full width at half maximum (FWHM) of the Eg Raman peak, becomes a reliable metric only when it is studied in conjunction with the FWHM of the A1g Raman peak. We demonstrate that the lower the FWHM of both the Eg and A1g peaks, the higher the crystalline quality of the in-plane and out-of-plane PtSe₂ films, respectively, and the higher the electrical conductivity. For semiconducting PtSe₂ bilayer films, high crystalline quality films with Eg and A1g FWHM values comparable to those of exfoliated crystals are obtained using a periodic Pt flux (periodic supply epitaxy). The bilayer to multilayer PtSe₂ films are not monocrystalline but present a fiber texture along the c-axis, which is typical on a sapphire substrate. The epitaxy of a thick PtSe₂ film on vicinal sapphire surfaces (steps) is demonstrated for the first time. Finally, we fabricated optoelectronic devices operating at 1.55 µm, the typical wavelength of optical fiber telecommunications. They are based on thick semi-metallic PtSe₂, exhibiting high electrical conductivity and good optical absorption at 1.55 µm, which is directly synthesized on a 2-inch sapphire substrate. We demonstrate PtSe₂-based photodetectors with a record bandwidth of 60 GHz and the first TMD-based optoelectronic mixer with, in addition, a bandwidth larger than 30 GHz

Two-dimensional materials arouse ever greater interest in the scientific community due to their electronic and optical properties. Among these 2D materials, the 2D family of transition metal dichalcogenides (TMDs) offers great potential for applications in optoelectronics and nanotechnology. Of these TMD nanomaterials, platinum diselenide PtSe2 has been extensively studied since the successful synthesis of a PtSe2 monolayer in 2015. In this chapter, the multilayer PtSe2 is investigated with first-principle calculations. In order to calculate the optical properties of the system, we first determine its dielectric function. From this, we can extract other optical functions, such as refractive index, extinction coefficient, absorption coefficient, and reflectivity. A good description of these properties can be enhanced by a detailed study of the material’s band structure.