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A single beam plasma source was used to deposit hydrogenated amorphous carbon (a-C:H) coatings at room temperature. Using methane source gas, a-C:H coatings were deposited at different radio frequency (RF) power to fabricate transparent and durable coatings. The film deposition rate was almost linearly proportional to the ion source power. Hydrogenated amorphous carbon films of ~100 nm thickness appeared to be highly transparent from UV to the infrared range with a transmittance of ~90% and optical bandgap of ~3.7 eV. The coatings also possess desirable mechanical properties with Young’s modulus of ~78 GPa and density of ~1.9 g/cm3. The combined material properties of high transmittance and high durability make the ion-source-deposited a-C:H coatings attractive for many applications. 

A single-beam plasma source was developed and used to deposit hydrogenated amorphous carbon (a-C:H) thin films at room temperature. The plasma source was excited by a combined radio frequency and direct current power, which resulted in tunable ion energy over a wide range. The plasma source could effectively dissociate the source hydrocarbon gas and simultaneously emit an ion beam to interact with the deposited film. Using this plasma source and a mixture of argon and C2H2 gas, a-C:H films were deposited at a rate of ∼26 nm/min. The resulting a-C:H film of 1.2 µm thick was still highly transparent with a transmittance of over 90% in the infrared range and an optical bandgap of 2.04 eV. Young’s modulus of the a-C:H film was ∼80 GPa. The combination of the low-temperature high-rate deposition of transparent a-C:H films with moderately high Young’s modulus makes the single-beam plasma source attractive for many coatings applications, especially in which heat-sensitive and soft materials are involved. The single-beam plasma source can be configured into a linear structure, which could be used for large-area coatings. 

Abstract A single-beam ion source was developed and used in combination with magnetron sputtering to modulate the film microstructure. The ion source emits a single beam of ions that interact with the deposited film and simultaneously enhances the magnetron discharge. The magnetron voltage can be adjusted over a wide range, from approximately 240 to 130 V, as the voltage of the ion source varies from 0 to 150 V, while the magnetron current increases accordingly. The low-voltage high-current magnetron discharge enables a ‘soft sputtering mode’, which is beneficial for thin-film growth. Indium tin oxide (ITO) thin films were deposited at room temperature using a combined single-beam ion source and magnetron sputtering. The ion beam resulted in the formation of polycrystalline ITO thin films with significantly reduced resistivity and surface roughness. Single-beam ion-source-enhanced magnetron sputtering has many potential applications in which low-temperature growth of thin films is required, such as coatings for organic solar cells. 

Integrative neural interfaces combining neurophysiology and optogenetics with neural imaging provide numerous opportunities for neuroscientists to study the structure and function of neural circuits in the brain. Such a comprehensive interface demands miniature electrode arrays with high transparency, mechanical flexibility, electrical conductivity, and biocompatibility. Conventional transparent microelectrodes made of a single material, such as indium tin oxide (ITO), ultrathin metals, graphene and poly-(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS), hardly possess the desired combination of those properties. Herein, ultra-flexible, highly conductive and fully transparent microscale electrocorticogram (μECoG) electrode arrays made of a PEDOT:PSS–ITO–Ag–ITO assembly are constructed on thin parylene C films. The PEDOT:PSS–ITO–Ag–ITO assembly achieves a maximum ∼14% enhancement in light transmission over a broad spectrum (350–650 nm), a significant reduction in electrochemical impedance by 91.25%, and an increase in charge storage capacitance by 1229.78 μC cm −2 . Peeling, bending, and Young's modulus tests verify the enhanced mechanical flexibility and robustness of the multilayer assembly. The μECoG electrodes enable electrical recordings with high signal-to-noise ratios (SNRs) (∼35–36 dB) under different color photostimulations, suggesting that the electrodes are resilient to photon-induced artifacts. In vivo animal experiments confirm that our array can successfully record light-evoked ECoG oscillations from the primary visual cortex (V1) of an anesthetized rat.