Thin Amorphous Carbon Layer Research Articles

Polyvinylpyrrolidone-assisted sol–gel synthesis of efficient Li2TiSiO5/C composite anodes for Li-Ion batteries

This study presents the process of developing an effective anode material for lithium-ion batteries (LIBs) by usage of Li2TiSiO5 coated with a thin layer of carbon (LTSO/C). The material was prepared through a sol–gel method, where varying amounts of polyvinylpyrrolidone (PVP) were used as a carbon source during the synthesis process. The physicochemical analysis of the LTSO/C samples indicates that as the amount of PVP used during sol–gel synthesis increases, the particle diameter of LTSO decreases. Furthermore, the analysis shows that a thin amorphous carbon layer is deposited on the LTSO surfaces, along with additional carbon networks between the LTSO particles. Based on the electrochemical analysis conducted to optimize the amount of PVP during synthesis, the resulting LTSO/C composite electrode synthesized with 1 g of PVP exhibits a specific capacity of 274.5 mAh·g−1 at 0.1C after 150 cycles, which is quite close to the theoretical capacity. In addition, this LTSO/C electrode demonstrates exceptional electrochemical performance when operated at high rates, surpassing a discharge capacity of 170 mAh g−1 up to 2C. Therefore, the LTSO/C is an excellent choice for high-performance anode material in LIBs.

Fabrication of thin diamond membranes by [formula omitted] implantation

Color centers in diamond are one of the most promising tools for quantum information science. Of particular interest is the use of single-crystal diamond membranes with nanoscale-thickness as hosts for color centers. Indeed, such structures guarantee a better integration with a variety of other quantum materials or devices, which can aid the development of diamond-based quantum technologies, from nanophotonics to quantum sensing. A common approach for membrane production is what is known as “smart-cut”, a process where membranes are exfoliated from a diamond substrate after the creation of a thin sub-surface amorphous carbon layer by He+ implantation. Due to the high ion fluence required, this process can be time-consuming. In this work, we demonstrated the production of thin diamond membranes by neon implantation of diamond substrates. With the target of obtaining membranes of ∼200 nm thickness and finding the critical damage threshold, we implanted different diamonds with 300 keV Ne+ ions at different fluences. We characterized the structural properties of the implanted diamonds and the resulting membranes through SEM, Raman spectroscopy, and photoluminescence spectroscopy. We also found that a SRIM model based on a two-layer diamond/sp2-carbon target better describes ion implantation, allowing us to estimate the diamond critical damage threshold for Ne+ implantation. Compared to He+ smart-cut, the use of a heavier ion like Ne+ results in a ten-fold decrease in the ion fluence required to obtain diamond membranes and allows to obtain shallower smart-cuts, i.e. thinner membranes, at the same ion energy.

Tribological Behaviour of Low Temperature Plasma Assisted Carburized 316 L Steel Produced by L-PBF Technique

Austenitic stainless steels produced by Laser Powder Bed Fusion (L-PBF) are interesting materials because of their excellent corrosion resistance. Due to their relatively low hardness, the tribological response of these materials is poor, which limits their use in applications where control of wear degradation is important. Nevertheless, low-temperature plasma-assisted carburisation is an interesting process for improving the wear resistance of austenitic stainless steels, as has been observed for wrought materials. In fact, the increase in hardness is guaranteed by a surface layer of expanded austenite (S-phase) with a thin top layer of amorphous carbon. In this work, AISI 316 L, produced by the L-PBF technique, was carburised using 5 different plasma gas mixtures (by varying the CH4/H2 ratio) at 475°C for 7 hours. The samples obtained were then subjected to a detailed microstructural characterisation in order to obtain information on surface modification. The morphological features of the surface were examined by SEM observations in top view and in cross-section. The tribological performance was evaluated by pin-on-flat tests (alumina sphere as counter-material) with 2 different applied loads and a stroke length of 5 mm. Friction coefficient, wear rate (stylus profilometer) and wear mechanisms (SEM) were also evaluated. Preliminary results show an increase in wear resistance of all plasma treated materials compared to the untreated material. The improved tribological performance was discussed in relation to the abrupt increase in surface hardness.

Nucleation and Growth of GaAs on a Carbon Release Layer by Halide Vapor Phase Epitaxy.

We couple halide vapor phase epitaxy (HVPE) growth of III-V materials with liftoff from an ultrathin carbon release layer to address two significant cost components in III-V device - epitaxial growth and substrate reusability. We investigate nucleation and growth of GaAs layers by HVPE on a thin amorphous carbon layer that can be mechanically exfoliated, leaving the substrate available for reuse. We study nucleation as a function of carbon layer thickness and growth rate and find island-like nucleation. We then study various GaAs growth conditions, including V/III ratio, growth temperature, and growth rate in an effort to minimize film roughness. High growth rates and thicker films lead to drastically smoother surfaces with reduced threading dislocation density. Finally, we grow an initial photovoltaic device on a carbon release layer that has an efficiency of 7.2%. The findings of this work show that HVPE growth is compatible with a carbon release layer and presents a path toward lowering the cost of photovoltaics with high throughput growth and substrate reuse.

Cryo‐TEM Study of High‐Performance Iron Difluoride Cathode Enabled by Low Temperature CVD Carbon Coating

AbstractMetal fluorides (MFs) are regarded as high‐capacity conversion cathode materials for next‐generation lithium‐ion batteries with high energy density. However, these cathodes suffer from poor electronic conductivity, sluggish reaction kinetics, and deleterious cathode solid electrolyte interface (CEI) formation, which may cause rapid cell degradation upon cycling. Herein, a low temperature chemical vapor deposition (CVD) carbon coating technology is successfully achieved to coat MFs‐FeF2 with a thin amorphous carbon layer, which promotes the formation of a stable CEI with improved electronic and ionic transport property. Consequently, a discharge capacity higher than 450 mAh g−1 of the CVD coated FeF2 is achieved with a capacity retention at about 75% after 2500 cycles in a saturated electrolyte. Moreover, an unprecedented cycling performance with the discharge capacity of 350 mAh g−1 after 500 cycles in a super diluted electrolyte is also achieved. Advanced cryo‐electron microscopy reveals that the carbon coating significantly suppresses the undesirable CEI formation and promotes the formation of a thin CEI with excellent chemo‐mechanical property. This work provides a feasible technology to stabilize the important interface on MFs and offers a new strategy to accelerate the commercial adoption of such cathodes.

Gas detonation-prepared nano-carbon-based capsule matrix materials: characterisation and microwave-absorption properties

Carbon-based capsule nanomaterials were synthesised through gas-phase detonation using acetylene gas, oxygen, and pentacarbonyl iron. The resulting nanoparticles consisted of a thin layer of capsule-like amorphous carbon with a high specific surface area and strong adsorption capacity. The products exhibited good electromagnetic properties with good reflection loss and absorption capabilities in the frequency range 2–18 GHz. The effective response frequency band ranged from 10.12 to 11.30 GHz, and the reflection loss reached 10.94 dB at 10.96 GHz. The absorption mechanism was mainly owing to dielectric loss as no significant magnetic loss was observed. These nanomaterials have the potential to be used as a matrix for carrying other nanomaterials and for adjusting the impedance-matching of composite materials, thereby enhancing electromagnetic-wave absorption.

Fe3Se4 rice grains anchored on cotton-derived porous carbon network for enhanced sodium ion storage and hydrogen evolution reactions

Transition-metal selenides have been regarded as promising anode materials for energy storage and conversion fields. However, their practical application is hindered by volume expansion, polyselenide dissolution, and sluggish kinetics. Herein, porous Fe3Se4 rice grains were successfully encapsulated on cotton derived carbon network (CN@Fe3Se4@C) by facile solvothermal method combined with in-situ selenization process. Beneficial from the unique structure, the CN@Fe3Se4@C electrode exhibits excellent sodium storage properties (302 mAh g−1 at 500 mA g−1 after 500 cycles) and hydrogen evolution reactions (HER) performance (an overpotential of 168 mV at a current density of 10 mA cm−2, and a low Tafel slope of 77 mV dec−1). Electrochemical mechanism investigations demonstrate that the carbon coated porous Fe3Se4 nanoparticles and ant nest-like carbon network can shorten the diffusion path for Na+ ions and suppress volume expansion. Meanwhile, the 3D interconnected porous carbon framework can provide multiple channels for fast electron transport and improve electron conductivity. In addition, the thin amorphous carbon layers on individual Fe3Se4 rice grains can well inhibit the shuttle effect of polysulfides and the agglomeration of Fe3Se4, ensuring fast kinetics and long-term stability. This study reveals the great potential of CN@Fe3Se4@C as active materials for sodium ion batteries and hydrogen production.

Preparation and characterization of fluorine-substituted LiFeBO3 with carbon coating to enhance electrochemical performance and stability as a cathode material for Li-ion batteries

The fluorine-substituted LiFeBO3 with carbon coating (LFeBF/C) has been successfully demonstrated via a solid-state reaction to enhance its electrochemical properties and stability in air. Transmission electron microscopy characterization reveals that the primary LFeBF particles are fully covered by a thin layer of amorphous carbon. The formation of vonsenite-type LFeBF/C and the distribution of Li ions into its octahedral sites due to the fluorine substitution are confirmed using X-ray diffraction and solid-state nuclear magnetic resonance measurements, respectively. The stability of the LFeBF/C in air is promoted by the carbon layer. After two months of open-air storage, no significant changes in X-ray diffraction patterns can be observed. The synergistic effects of fluorine substitution and carbon coating enhance the overall electrochemical performance of the LFeBF/C as achieving a superior initial discharge capacity of 367.0 mAh g−1 at the rate of 0.05C and 231.7 mAh g−1 at 1.0C. In addition, the cyclic stability of the LFeBF/C is improved, reaching 197.5 mAh g−1 at the rate of 1.0C after 50 cycles, which corresponds to a retention of 85% of its initial capacity.

Investigation of a Highly Sensitive Surface-Enhanced Raman Scattering Substrate Formed by a Three-Dimensional/Two-Dimensional Graphene/Germanium Heterostructure.

Three-dimensional graphene (3D-graphene) is used in surface-enhanced Raman spectroscopy (SERS) because of its plasmonic nanoresonator structure and good ability to interact with light. However, a thin (3-5 nm) layer of amorphous carbon (AC) inevitably appears as a template layer between the 3D-graphene and object substrate when the 3D-graphene layer is synthesized, weakening the enhancement factor. Herein, two-dimensional graphene (2D-graphene) is employed as a template layer to directly synthesize 3D-graphene on a germanium (Ge) substrate via plasma-assisted chemical vapor deposition, bypassing the formation of an AC layer. The interaction and photoinduced charge transfer ability of the 3D-graphene/Ge heterojunction with incident light are improved. Moreover, the high density of electronic states close to the Fermi level of the heterojunction induces the adsorbed probe molecules to efficiently couple to the 3D-graphene-based SERS substrate. Our experimental results imply that the lowest concentrations of rhodamine 6G and rhodamine B that can be detected on the 3D/2D-graphene/Ge SERS substrate correspond to 10-10 M; for methylene blue, it is 10-8 M. The detection limits of the 3D/2D-graphene/Ge SERS substrate with respect to 3-hydroxytyramine hydrochloride and melamine (in milk) are both less than 1 ppm. This work may provide a viable and convenient alternative method for preparing 3D-graphene SERS substrates. It also constitutes a new approach to developing SERS substrates with remarkable performance levels.

Deposition of nano-crystalline tungsten carbide powders from gaseous WO2(OH)2

Lower WC grain sizes in the nanometer range have positive effects on the properties of hardmetals (e.g., hardness), but the established production processes of WC are limited to grain sizes of about 150 nm. To produce WC powder with grain sizes in the lower nanometer range, an alternative WC production process based on the chemical vapor transport (CVT) reaction of WO3 and H2O forming gaseous WO2(OH)2 at about 1100 °C, followed by a carburation reaction with H2/CH4-gas mixtures was investigated. The influences of different process parameters such as furnace temperature, humidity and gas flows were investigated to improve the process. With the right set of parameters the produced powder consisted mainly of agglomerated WC grains with a size of about 5 nm. Beside the common hexagonal WC phase, the cubic WC1−x phase was stabilized due to the small crystallite sizes. In addition, a thin layer of amorphous carbon was present on the powder surface due to the catalytic methane decomposition on the WC surface. The amount of oxidic and metallic residues in the product powder was minimized with the parameter optimization and the powder yield was increased up to about 50%. With further optimization of the process parameters and usage of improved flow breakers, the purity and yield of the product powder can be further improved. Since an application in the hardmetal section is not realistic at the moment, applications in the catalysis sector could be considered due to the small grain size and good catalytic activity of the cubic WC1−x phase.

Fast Surface Dynamics on a Metallic Glass Nanowire.

The dynamics near the surface of glasses can be much faster than in the bulk. We studied the surface dynamics of a Pt-based metallic glass using electron correlation microscopy with sub-nanometer resolution. Our studies show an ∼20 K suppression of the glass transition temperature at the surface. The enhancement in surface dynamics is suppressed by coating the metallic glass with a thin layer of amorphous carbon. Parallel molecular dynamics simulations on Ni80P20 show a similar temperature suppression of the surface glass transition temperature and that the enhanced surface dynamics are arrested by a capping layer that chemically binds to the glass surface. Mobility in the near-surface region occurs via atomic caging and hopping, with a strong correlation between slow dynamics and high cage-breaking barriers and stringlike cooperative motion. Surface and bulk dynamics collapse together as a function of temperature rescaled by their respective glass transition temperatures.

Photothermal excitation efficiency enhancement of cantilevers by electron beam deposition of amorphous carbon thin films

In recent years, the atomic force microscope has proven to be a powerful tool for studying biological systems, mainly for its capability to measure in liquids with nanoscale resolution. Measuring tissues, cells or proteins in their physiological conditions gives us access to valuable information about their real ‘in vivo’ structure, dynamics and functionality which could then fuel disruptive medical and biological applications. The main problem faced by the atomic force microscope when working in liquid environments is the difficulty to generate clear cantilever resonance spectra, essential for stable operation and for high resolution imaging. Photothermal actuation overcomes this problem, as it generates clear resonance spectra free from spurious peaks. However, relatively high laser powers are required to achieve the desired cantilever oscillation amplitude, which could potentially damage biological samples. In this study, we demonstrate that the photothermal excitation efficiency can be enhanced by coating the cantilever with a thin amorphous carbon layer to increase the heat absorption from the laser, reducing the required excitation laser power and minimizing the damage to biological samples.

In-situ synthesis of SiC/Fe nanowires coated with thin amorphous carbon layers for excellent electromagnetic wave absorption in GHz range

Electromagnetic absorbents with peculiarities of light-weight, beneficial structure, broadband, adequate corrosion resistance, and facile synthesis route are always highly practical in the telecom and stealth fields. In this regard, a new type hybird material (SiC/Fe)@C nanowires (NWs) has been effectively synthesized through an in-situ vapor-liquid-solid growth confined at arc-plasma region. A (SiC/Fe)@C NW is composed of a dielectric SiC NW with a magnetic Fe nanoparticle at it tip, both tightly encapsulated by conductive graphene-like carbon nanolayers at the surfaces. Such carbon-coated NWs form a randomly interconnected network, endowing a proper impedance matching to microwave and an anti-corrosion ability. It is found that the composite of (SiC/Fe)@C NWs and paraffin with a 25 wt% loading has shown the lowest reflection loss (RL) of −63.44 dB at 12.4 GHz, with a wide effective absorption band (RL ≤ −10 dB) of 7 GHz in thickness of 1.95 mm. This superb RL is attributed to the synergic outcomes from the balanced dielectric/magnetic losses with an appropriate impedance matching, resulted from the intrinsic physical properties and special structures of the (SiC/Fe)@C NWs. Pseudo percolation threshold, near 30 wt% loading of (SiC/Fe)@C NWs in the electromagnetically transparent matrix, implies the significant efficacy of concentration/distribution of absorbent on RL performances.

Pseudocapacitive deionization of uranium(VI) with WO3/C electrode

Decontamination and recovery of uranium(VI) [U(VI)] from radioactive wastewater is vital to sustainable nuclear power production and reclamation of radioactive waste. As a promising technology of water treatment, capacitive deionization for adsorption of U(VI) started to attract attention. Herein, for the first time, a floriform WO3/C composite was developed as a pseudocapacitive electrode material for electrosorption of U(VI) from water. The as-prepared WO3/C composite was constructed from dozens of 2D nanosheets with a thin amorphous carbon layer, resulting in uniform flower-like particles with hierarchical nanostructure and superior open pore network. The charge/discharge process of WO3/C was demonstrated as prominent capacitive controlled behavior by quantization of capacitance contributions. As a result, the WO3/C electrodes achieved a maximum U(VI) electrosorption capacity of 449.9 mg g−1 at 1.2 V and good cycling stability after consecutive adsorption-desorption, which is superior to the conventional physical adsorption processes. The superior CDI performance of the WO3/C electrode is credited to the synergistic effect of EDLs and pseudocapacitance based on the combination of WO3 and carbon layer with hierarchical nanostructure. Overall, the facile preparation strategy, the superior electrosorption performances, and the high cycling stability, endow the floriform WO3/C electrodes to be a promising electrode material for electrosorption of U(VI) from wastewater.

Evaluation on the interface characteristics, thermal conductivity, and annealing effect of a hot-forged Cu-Ti/diamond composite

A Cu-1.5 wt.%Ti/Diamond (55 vol.%) composite was fabricated by hot forging from powder mixture of copper, titanium and diamond powders at 1050 °C. A nano-thick TiC interfacial layer was formed between the diamond particle and copper matrix during forging, and it has an orientation relationship of (111)TiC//(002)Cu&[1 1¯ 0]TiC//[1 1¯ 0]Cu with the copper matrix. HRTEM analysis suggests that TiC is semi-coherently bond with copper matrix, which helps reduce phonon scattering at the TiC/Cu interface and facilitates the heat transfer, further leading to the hot-forged copper/diamond composite (referred as to Cu-Ti/Dia-0) has a thermal conductivity of 410 W/mK, and this is about 74 % of theoretical thermal conductivity of hot-forged copper/composite (552 W/mK). However, the formation of thin amorphous carbon layer in diamond particle (next to the interfacial TiC layer) and deformed structure in the copper matrix have adverse effect on the thermal conductivity of Cu-Ti/Dia-0 composite. 800 °C-annealing eliminates the discrepancy in TiC interface morphology between the diamond-{100} and -{111} facets of Cu-Ti/Dia-0 composite, but causes TiC particles coarsening and agglomerating for the Cu-Ti/Dia-2 composite and interfacial layer cracking and spallation for the Cu-Ti/Dia-1 composite. In addition, a large amount of graphite was formed by titanium-induced diamond graphitization in the Cu-Ti/Dia-2 composite. All these factors deteriorate the heat transfer behavior for the annealed Cu-Ti/Dia composites. Appropriate heat treatment needs to be continually investigated to improve the thermal conductivity of hot-forged Cu-Ti/Dia composite by eliminating deformed structure in the copper matrix with limit/without impacts on the formed TiC interfacial layer.

Facile fabrication of double-shelled hollow SnO2@C nanoparticles with improved lithium storage via a novel heterogeneous template strategy

Tin dioxide (SnO2) has been considered as one of the most promising candidates to surpass the capacity limitation of conventional graphite anode of lithium-ion batteries. However, the tremendous volume change of SnO2 generated during cycling process gives rise to poor cycling performance and thus seriously impedes the practical use of SnO2 anode in lithium-ion batteries. It is suggested that fabrication of double-shelled hollow nanostructured SnO2/C composites is expected to be able to solve above problem effectively, but is difficult to be achieved because of the increased complexity of the structures. Herein, we for the first time demonstrate a novel heterogeneous template strategy to facilely fabricate double-shelled hollow SnO2@C nanoparticles (DSH SnO2@C). It is worthy of noting that the double-shelled hollow structure is formed in one-step hydrothermal process, due to the rational adoption of a heterogeneous template and therefore shows facile characteristic. The shells of DSH SnO2@C consist of ultra-fine SnO2 nanocrystals as well as the outer ultra-fine SnO2 nanocrystals are further coated by a thin layer of amorphous carbon, hence have many structural characteristics such as large specific surface area, rich pores, adequate free space, and carbon coating. As expected, the as-prepared DSH SnO2@C presents improved lithium storage performance as an anode for lithium-ion batteries, exhibiting a high capacity of 769 mAh g−1 at 200 mA g−1 after even 350 cycles, which is around 98.6% retention of the second cycle. Moreover, thus concept of heterogeneous template strategy may be extended to design and fabrication of other metal oxides-based nanocomposites with double-shelled hollow structures for application in other various fields such as catalysis, drug delivery and sensor.

Improving the electromagnetic shielding of fabricated NdFeB particles by a coating thin carbonaceous layer

Fabrication and improvement of electromagnetic interference (EMI) shielding products have recently been the subject of intense research. In the present study, the NdFeB magnetic powder was used in prolonged high-energy wet ball milling to synthesize and enhance properties of the magnetic filler of EMI shielding composites. The physicochemical changes induced in particles prepared by the process confirmed that the applied oleic acid surfactant was simply converted into a thin amorphous carbon layer on NdFeB nanoparticles. Increasing the amount of surfactant in the ball milling procedure caused a thicker layer of the carbonaceous blend to be formed on magnetic nanoparticles. We found that the thicker layer of the amorphous carbon covering the synthesized magnetic particles increased the real and imaginary dielectric permittivity of the resulting product about 15% and 95%, respectively. This also increased the shielding absorption efficiency (SEA) about 40% and the total shielding efficiency (SET) about 30% at some frequencies. Furthermore, more carbonaceous surfactant in composite (II) improved impedance matching, leading to a decrease in reflection loss and an increase in microwave absorption of the composite.

Prussian blue analogs (PBA) derived porous bimetal (Mn, Fe) selenide with carbon nanotubes as anode materials for sodium and potassium ion batteries

The development of sodium/potassium-ion batteries with excellent performance would break the conflict between the limited lithium resources and low-price requirement of lithium-ion batteries. However, because of the bigger sizes of sodium/potassium ion in comparison to lithium ion, the requirement of anode materials with suitable structure for sodium/potassium ions insertion/extraction is still challenging. Here, porous MnSe/FeSe2 (Mn-Fe-Se) adhered/inserted with interlaced carbon nanotubes (CNTs) have been successfully designed and prepared via a simple chemical precipitation approach and a subsequent one-step carbonization-selenization of Mn-Fe Prussian blue analogs precursor process. Characterization results demonstrate that the prepared Mn-Fe-Se/CNTs with high conductive network architecture are constructed by Mn-Fe-Se sphere adhered/inserted with interlaced CNTs, each Mn-Fe-Se sphere is assembled using several tens of nanoparticles and numerous voids, and the individual nanoparticle is uniformly coated by a thin nitrogen-doped amorphous carbon layer. Due to such unique porous architecture and synergistic effect of the heterogeneous components, Mn-Fe-Se/CNTs anode possesses reversible sodium/potassium storage with excellent rate performance and prominent cycling stability. Furthermore, the sodium and potassium storage mechanisms and kinetics verify the fundamental principles of improved electrochemical performance. This study will shed light on the development of other metal selenides with interlaced carbon nanotubes for high-performance sodium/potassium-ion batteries and other energy storage equipment.

Structural properties of protective diamond-like-carbon thin films grown on multilayer graphene

In spite of the versatility of electronic properties of graphene, its fragility and low resistance to damage and external deformations reduce the practical value of this material for many applications. Coating of graphene with a thin layer of hard amorphous carbon is considered as a viable solution to protect the 2D material against accidental scratches and other external damaging impacts. In this study, we investigate the relationship between the deposition condition and quality of diamond-like-carbon (DLC) on top of multilayer graphene by means of molecular dynamics simulations. Deposition of carbon atoms with 70 eV incident energy at 100 K resulted in the highest content of -bonded C atoms. An increase of the number of dangling bonds at the interface between the top graphene layer and the DLC film indicates that decrease of the incident energy reduces the adhesion quality of DLC thin film on graphene. Analysis of radial distribution function indicates that hybridized carbon atoms tend to grow near already existing -atoms. This explains why the quality of the DLC structures grown on graphene have generally a lower content of C atoms compared to those grown directly on diamond. Ring analysis further shows that a DLC structure grown on the -rich structures like graphene contains a higher fraction of disordered ring structures.

SEY and low-energy SEY of conductive surfaces

The study of Secondary Electron Yield (SEY) is widely performed to address important properties of materials to be used in a very wide spectrum of applications. It is, therefore, extremely important to understand the SEY dependence on material type, surface contaminants, structural quality and surface damage. We review here our recent studies of such items performed by looking at some representative conductive materials as noble metals and carbon based surfaces. Polycrystalline Ag, Au and Cu samples have been studied as introduced in the ultra-high vacuum chamber (therefore with an significant surface contamination) and after having been cleaned by ion sputtering. The comparison between the curves confirms that the SEY behavior is strongly influenced by the chemical state of the metal surfaces. We demonstrate the ability of SEY to determine work function values with high accuracy if the experimental system allows using very slow primary electrons. We also investigated, for the Cu sample, the effect on SEY of minimal amount of contaminants in the sub-monolayer regime showing that SEY is highly sensitive to the presence of adsorbates even at such very low coverages, specially for low energy primary electrons. In the case of C surfaces we summarize here the effect that the structural ordering of the C lattice has on the macroscopic SEY properties of ultrathin C layers. In particular we followed the SEY evolution during the thermal graphitization of thin amorphous carbon layers and during the amorphization of highly oriented pyrolytic graphite by means of Ar+ bombardment. In the first case the SEY decrease observed with the progressive conversion of sp3 hybrids into six-fold aromatic domains was related to the electronic structure of the C-films close to the Fermi level. We found that a moderate structural quality of the C layer, corresponding to aromatic clusters of limited size, is sufficient to obtain a SEY as low as ∼1. For the bombarded graphite, the strong lattice damage remains limited to the near surface layer, where the high density of defects reduces the transport of incoming and secondary electrons. Then, the SEY curves resulted differently modified in the low and high primary energy regions, but their maximal values remained favorably low. Our findings demonstrate that SEY, besides being an indispensable mean to qualify technical materials in many technological fields, can be also used as a flexible and advantageous diagnostics to probe surfaces and interfaces.