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Millimeter-Scale Growth of Single-Oriented Graphene on a Palladium Silicide Amorphous Film
摘要： It is widely accepted in condensed matter physics and material science communities that a single-oriented overlayer cannot be grown on an amorphous substrate because the disordered substrate randomizes the orientation of the seeds, leading to polycrystalline grains. In the case of two-dimensional materials such as graphene, the large-scale growth of single-oriented materials on an amorphous substrate has remained unsolved. Here, we demonstrate experimentally that the presence of uniformly oriented graphene seeds facilitates the growth of millimeter-scale single-oriented graphene with 3×4 mm2 on palladium silicide, which is an amorphous thin film, where the uniformly oriented graphene seeds were epitaxially grown. The amorphous palladium silicide film promotes the growth of the single-oriented growth of graphene by causing carbon atoms to be diffusive and mobile within and on the substrate. In contrast to these results, without the uniformly oriented seeds, the amorphous substrate leads to the growth of polycrystalline graphene grains. This millimeter-scale single-oriented growth from uniformly oriented seeds can be applied to other amorphous substrates.
关键词： silicon carbide,amorphous substrate,single orientation,graphene,palladium silicide
更新于2025-09-23 15:23:52
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Formation of Cobalt Impurity Microinclusions in Silicon Single Crystals
摘要： The structure and chemical composition of cobalt impurity microinclusions in silicon have been studied by electron probe microanalysis using n- and p-type Si?Co? samples prepared by diffusion doping and cooled at different rates after diffusion annealing. The cooling rate after diffusion annealing has been shown to have a significant effect on the structural parameters of the samples and the size of the forming impurity microinclusions. The size and shape of the impurity microinclusions determine their distribution over the bulk of the samples.
关键词： cobalt microinclusions,cobalt silicide,cooling rate,electron probe microanalysis
更新于2025-09-23 15:23:52
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PdEr-Silicide Formation and Contact Resistivity Reduction to n-Si(100) Realized by Dopant Segregation Process
摘要： In this paper, we have investigated the PdEr-silicide formation utilizing a developed PdEr-alloy target for sputtering, and evaluated the contact resistivity of PdEr-silicide layer formed on n-Si(100) by dopant segregation process for the first time. Pd2Si and ErSi2 have same hexagonal structure, while the Schottky barrier height for electron (Φbn) is different as 0.75 eV and 0.28 eV, respectively. A 20 nm-thick PdEr-alloy layer was deposited on the n-Si(100) substrates utilizing a developed PdEr-alloy target by the RF magnetron sputtering at room temperature. Then, 10 nm-thick TiN encapsulating layer was in-situ deposited at room temperature. Next, silicidation was carried out by the RTA at 500°C for 5 min in N2/4.9%H2 followed by the selective etching. From the J-V characteristics of fabricated Schottky diode, qΦbn was reduced from 0.75 eV of Pd2Si to 0.43 eV of PdEr-silicide. Furthermore, 4.0x10?8Ωcm2 was extracted for the PdEr-silicide to n-Si(100) by the dopant segregation process.
关键词： contact resistivity,PdEr-alloy target,RF magnetron sputtering,schottky barrier height,silicide
更新于2025-09-23 15:22:29
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Shape and orientation controlled hydrothermal synthesis of silicide and metal dichalcogenide on a silicon substrate
摘要： Shape-controlled MoS2 has been grown directly on a silicon substrate, for the first time, using a facile hydrothermal synthesis approach. The growth morphology is dependent on the substrate orientation. Square, hexagonal and triangular patterns of MoS2 are grown on Si (100), Si (110) and Si (111), respectively. Detailed studies reveal that Mo silicide is formed at the initial stage, and the formation of silicide patterns is dictated by the different surface energies of Si (100), Si (110) and Si (111). Subsequently, shaped MoS2 patterns are formed following the silicide ones at the thermodynamic equilibrium. The approach for the formation of these patterns can be generalized to other 2D materials and can also be formed in a large scale by a lithography method. The work has shown a new technique to form silicide via solution processing and grow patterned 2D materials directly on silicon substrates, which may have the potential for advancing the next-generation electronic devices.
关键词： Metal dichalcogenide,Silicide,Hydrothermal,Pattern
更新于2025-09-23 15:21:01
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Low Work Function Ytterbium Silicide Contact for Doping-Free Silicon Solar Cells
摘要： Metal silicide is a well-known material for contact layers, however, it has not been tested in the context of doping-free carrier selective contacts. Thin film deposition of an appropriate metal with mild annealing treatment is an interesting alternative to the more complex depositions of other compound materials. Reaction of Yb deposited on top an i-a-Si:H passivation layer results in the formation of YbSix on top of a remnant i-a-Si:H following a low-temperature anneal below 200 °C. Such a contact is an interesting candidate as a doping-free electron-selective contact. Detailed investigation of the i-a-Si/YbSix contact shows that Yb thickness, i-a-Si:H thickness and silicidation annealing conditions play a significant role in determining the recombination current density (J0,metal) and the contact resistivity (ρc). Low J0,metal of 5 fA/cm2 and low ρc below 0.1 ?.cm were independently demonstrated for such i-a-Si:H/YbSix contacts. We also demonstrate that low-temperature silicidation can be combined with contact sintering (160 °C/25 min) or module lamination (160 °C/20 min), which are potential pathways for process simplification. Combining the optimised i-a-Si:H/YbSix electron contact with MoOx based hole contact in the MolYSili doping-free cell (i-a-Si:H/MoOx+ i-a-Si:H/YbSix), we achieved 16.7 % in average efficiency and 17.0 % for the champion cell. Furthermore, the YbSix contact stability was evaluated at module level and excellent thermal stability of the MolYSili laminate was demonstrated using the damp-heat test method (humidity 85 %, 85 °C, 1000 h), where the laminated MolYSili cell did not show any degradation in the cell efficiency. This is the first proof-of-concept demonstration of a stable silicide-based contact for low-temperature processed doping-free solar cells.
关键词： Yb silicide,electron-selective contact,passivating contact,doping-free cells,pinning
更新于2025-09-23 15:19:57
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Thermoelectric Properties of (100) Oriented Silicon and Nickel Silicide Nanocomposite Films Grown on Si on Insulator and Si on Quartz Glass Substrates
摘要： We have grown (100) oriented composite films of Si and Ni silicide nanocrystals (Ni–Si NC film) on substrates of Si on insulator (SOI) and Si on quartz glass (SOQ). Owing to improvement of carrier transport properties and reduction of the thermal conductivity in the oriented films, they have higher dimensionless figures of merit, ZT of 0.22–0.42 for p-type Ni–Si NC film and 0.08–0.13 for n-type Ni–Si NC film than that of bulk Si (ZT < 0.01) at 30°C. The ZT values of p-type and n-type Ni–Si NC films were increased to 0.65 and 0.40 at 500°C, respectively.
关键词： silicon based thermoelectric materials,nanocomposite films,nickel silicide nanocrystals,silicon nanostructures,phonon scattering
更新于2025-09-19 17:15:36
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Effect of Si substrate modification on improving the crystalline quality, optical and electrical properties of thermally-evaporated BaSi2 thin-films for solar cell applications
摘要： We have grown orthorhombic barium disilicide (BaSi2) thin-films on modified silicon (Si) substrates by a thermal evaporation method. The surface modification of Si substrate was performed by a metal-assisted chemical etching method. The effects of etching time te on crystalline quality as well as optical and electrical properties of the BaSi2 films were investigated. The obtained results showed that substrate modification can enhance the crystalline quality and electrical properties; reduce the light reflection; and increase the absorption of the BaSi2 thin-films. The te of 8 s was chosen as the optimized condition for surface modification of Si substrate. The achieved inferred short-circuit current density, Hall mobility, and minority carrier lifetime of the BaSi2 film at te of 8 s were 38 mA/cm2, 273 cm2/Vs, and 2.3 μs, respectively. These results confirm that the BaSi2 thin-film evaporated on the modified Si substrate is a promising absorber for thin-film solar cell applications.
关键词： hall mobility,substrate modification,photoresponse,silicide semiconductor,Barium disilicide,minority carrier lifetime,optical property,thermal evaporation
更新于2025-09-19 17:13:59
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Observation of heterostructure epitaxy of Pt-doped Ni-monosilicide on Si(001)
摘要： The objective of this study was to determine detailed microstructure of a Ni1–xPtxSi ?lm formed via a melting/quenching process using high temperature laser annealing on a Si(001) substrate. The orthorhombic Ni1–xPtxSi ?lm was found to be able to epitaxially grow with a crystallographic relationship of Ni1–xPtxSi[010]//Si[110], Ni1–xPtxSi(400)//Si(331), and Ni1–xPtxSi (104)//Si(004). Volume expansion of the Ni1–xPtxSi ?lm due to Pt incorporation was mainly accommodated by an increase in only one direction nearly parallel to the ?lm surface (lattice parameter a). This was explained by the minimum coherent strain at the Ni1–xPtxSi (104)/Si(004) interface with an epitaxial growth tendency. Atomic-scale scanning transmission electron microscopy analyses revealed that the interface of Ni1–xPtxSi/Si had a repetitive atomic-step feature with energetically favorable Ni1–xPtxSi(004) terraces and (400) structural ledges that could increase the coherent area. By generating an array of mis?t dislocations with an extra half plane of Ni1–xPtxSi(020), the elastic strain was further relieved.
关键词： Ni-silicide,Epitaxy,Thin ?lm,Structural ledges,Interface,Microstructure
更新于2025-09-10 09:29:36
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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - First Principles Calculations of the Effect of Stress in the I-V Characteristics of the CoSi<inf>2</inf>/Si Interface
摘要： We present ab initio-based electronic transport calculations on the effect of uniaxial and bi-axial stress on the CoSi2/nSi interface resistivity for the three main silicon crystallographic directions. For the [001] case, we identify two distinctive low and high bias conduction regimes for both compressive and tensile stress. In these regimes, the current is dominated by electronic transmission pathways near the Γ point for bias up to ~0.1V, while for higher bias it is dominated by transmission at the (±1/2, ±1/2) conduction band valleys of the Brillouin zone, which results in a contact resistivity decrease of up to 30% at 0.2V bias. This effect is less pronounced for the [110] direction, and negligible for the [111] case due to the symmetry of the Si conduction band valleys along these directions. This study provides insight into stress-based optimization pathways for contact resistivity reduction of silicide interfaces in next generation semiconductor devices.
关键词： silicide,Ab initio,electronic transport,contact resistivity
更新于2025-09-04 15:30:14