Oxidative Chemical Vapor Deposition Research Articles

Elimination of the Low Resistivity of Si Substrates in GaN HEMTs by Introducing a SiC Intermediate and a Thick Nitride Layer

We report the effect of a thick nitride layer on the high-frequency performance of AlGaN/GaN highelectron-mobility transistors (HEMTs) grown by metal oxide chemical vapor deposition (MOCVD) on a 6-inch Czochralski (Cz)-Si substrate. The thick nitride layer was grown via a 3C-SiC intermediate layer. A significantly low parasitic pad capacitance and a comparable cutoff frequency of 4.5 GHz for 2-μm gate length devices were achieved along with excellent electron transport characteristics, such as a mobility of ~2200 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V-s and a drain current density of 520 mA/mm. The extracted small-signal equivalentcircuit parameters also verified the accuracy of the measured cutoff frequency and parasitic capacitances.

Integration of PEGylated Polyaniline Nanocoatings with Multiple Plastic Substrates Generates Comparable Antifouling Performance.

Conducting polymer nanocoatings render plastics to possess interesting optical, chemical, and electrical properties. It nevertheless remains technically challenging to deposit uniform conducting polymer nanocoatings on ambient plastic substrates ascribed to the inert and varied chemical properties of plastics and the notorious processability of conducting polymers. Previous studies have made progress in delivering various conducting polymer thin films via oxidative chemical vapor deposition. Herein, we develop a solution-based approach to polyaniline (PANI) and PEGylated PANI nanocoatings on multiple engineering plastics followed by evaluating their antifouling performance. The procedure relies on the formation of uniform, lyotropic V2O5·nH2O thin films on plastics assisted by a surfactant-sodium N-lauroylsarcosinate. Next, in situ, oxidative polymerization causes the formation of nanofibrous PANI nanocoatings. Finally, interfacial functionalization leads to PEGylated PANI nanocoatings, and the steric nanolayer effectively repels the adsorption of bovine serum albumin and the attachment of the bacterium Pseudoalteromonas sp. on the surface. It is worth noting that the antifouling properties rely mainly on the presence of PEGylated PANI nanocoatings, irrespective of the type of plastic substrates underneath. The current study therefore opens an avenue for the solution-based delivery of conducting polymer-based, functional nanocoatings on hydrophobic substrates in a controllable manner with the availability of further modification.

An out of the box vision over oxidative chemical vapor deposition of PEDOT involving sublimed iron trichloride

Oxidative chemical vapor deposition (oCVD) is an efficient technique to produce highly conductive films of Poly (3,4-ethylenedioxythiophene) (PEDOT). Despite numerous studies on the oCVD of PEDOT films, there is limited information on the stability of the sublimation of solid oxidants and on their impact on the polymerization reactions. In this work, we use an in situ Quartz Crystal Microbalance to monitor film formation over time. Through a series of deposition experiments between 20 °C and 100 °C and for FeCl3/EDOT molar gas ratios between 17.3 and 75.3, we analyze in detail the correlations between process parameters and film morphology, composition, surface topography and electrical conductivity on 10 cm silicon wafers. By using multiple substrates at different positions into the reactor, we demonstrate that the formation of PEDOT occurs uniformly through purely surface reactions, following step growth polymerization principles. These results pave the way towards highly conductive oCVD PEDOT films processed from convenient solid oxidants.

Electro-Polymerization of Hydrogen-Bonding Conductive Polymers As Metal-Free Electrocatalysts for Energy Conversion

Electrocatalytic hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO2RR) are the key reactions for conversion of renewable electricity into storable chemical energies. It is crucially important to develop active and stable electrocatalysts without relying on rare metal elements for sustainable energy systems. Recently, some metal-free conductive organic polymers such as polydopamine (PDA) and poly guanine (PGA) synthesized by oxidative chemical vapor deposition (oCVD) have been found to exhibit high catalytic activity and durability for HER and CO2RR1,2. In addition to their conductivity of the π-conjugated system of the main chain, these polymers contain heteroatoms such as N and O at high densities, which are believed to act as hydrogen bonding sites for stabilization of reaction intermediates. However, their exact structures and relationship to the catalytic activities are not fully grasped.In this study, we employ electro-polymerization as the mean to obtain catalytic polymers. Taking polyaniline (PANI) as the host, hydrogen bonding monomers such as dopamine (DA), guanine (GA) and neutral red (NR) are to be introduced to obtain co-polymers with controlled structure and density of the hydrogen bonding sites. Comparison of their electrocatalytic activity to those of the respective homo-polymers should reveal the effective catalytic sites and its product selectivity, which should result in optimal design of the catalyst.Electro-polymerization of PANI and PNR was carried out at an ITO glass substrate in an aqueous solution containing 50 mM ANI or NR and 0.1 M H2SO4 during 50 times potential cycling between -0.5 and +0.6 V vs. Ag/AgCl under the N2. Copolymers were obtained by mixing the monomers at appropriate ratios. The films were characterized by FT-IR spectra.PANI, PNR and their copolymer appeared dark green, dark red and black, respectively. While CVs during electropolymerization of PANI continue to increase the redox peaks of PANI as typically expected, those for PNR show decrease of anodic current suggesting inactiveness of PNR for its redox (Figs. 1 a, b). When they are mixed together, a new redox peak in between those from PANI and another irreversible anodic peak close to +0.9 V appear, which indicate loading of NR in redox active form into PANI (Fig. 1c). The FTIR spectrum of the copolymer showed significant difference from the homo-polymers of PANI and PNR with intense absorption peaks between 800 and 1600 cm-1 (Fig. 1d). These peaks arise from infrared-activated vibrations (IRAV) due to the presence of polaron in the main chain, thus are indicative of its conductive nature. These results suggest improvement of conductivity by heterogeneity in copolymers. Its relevance to the catalytic property and optimal density of hydrogen bonding sites are to be further investigated.

Synthesis of Poly-Neutral Red and Its Electrocatalytic Property Towards CO2 Reduction Reaction

Concentration of carbon dioxide (CO2) in the atmosphere has steadily increased since industrial revolution. Despite the recent significant cost reduction of renewable electricity by solar and wind, their intermittency hinders the total shift to renewable energy. It is urgently needed to develop technologies for fast conversion of electrical energy into storable chemical energy by electrolysis, e.g., by water splitting and CO2 reduction. Stable and high-performance electrocatalysts are essential but must be developed without depending on precious metals for the real use and sustainability of the technology.Recently, we have demonstrated high and stable electrocatalytic properties of conductive organic polymers, such as polydopamine (PDA) and polyguanine (PGA) for hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR)1,2). Hydrogen bonding N and O atoms introduced to these polymers are expected to stabilize the reaction intermediates for their high catalytic activities. In this study, a phenazine dye, neutral red (NR) was employed as the monomer to obtain a metal-free catalyst. NR bears many amino functions to make it electropolymerizable just like poly-aniline (electropolymerization deposition, to be called EPD). Also, oxidative chemical vapor deposition (oCVD) was employed to obtain PNR. Synthesis, characterization and comparison of the catalytic activities of PNR by EPD and oCVD are discussed.EPD of PNR onto carbon felt (CF) was carried out by cycling potential between -1 and +1 V vs. Ag/AgCl for 100 cycles in an aqueous solution containing 0.2 mmol/L NR and 0.5 mol/L KNO3 (pH 5) at 50 mV/s. oCVD of PNR was performed in a three-zone quartz tube furnace under N2 flow, while setting the temperature for NR, sulfuric acid and CF at 375, 220 and 100ºC, respectively, for 240 min. PNR-modified as well as bare CF electrodes were measured under N2 and CO2 in a 1 M KNO3 (pH 7) for their catalytic activities for HER and CO2RR.While bare carbon felt (CF) electrode does not show any catalytic activity towards CO2RR, showing about -3 mA cm-2 current at –1 V vs. Ag/AgCl, supposedly dominated by that for HER, the PNR coated CFs show enhanced current (Fig. 1a). That by EPD gives about -5 and -6 mA under N2 and CO2, respectively, indicating its moderate catalytic activity for HER and CO2RR. PNR prepared by oCVD, on the other hand, gives -6 and -12 mA, to demonstrate its superior activity, especially for CO2RR. Chronoamperogram measured during long term electrolysis for 17 h at the oCVD PNR electrode indicates reasonable stability of the catalysis (Fig 1b). These results already nicely confirm catalytic activity of PNR for its conductivity and hydrogen-bonding ability.

Constitution and Conductivity of Metalloporphyrin Tapes

Metalloporphyrin tapes form in a solvent‐free oxidative chemical vapor deposition process on glass substrates. The metal center (M = NiII, CuII, ZnII, CoII, PdII, FeIIICl, 2H) in the 5,15‐disubstituted porphyrin monomer affects the initial C–C coupling step and consequently the formation of triply or doubly linked porphyrin tapes as well as the interchain interaction in the tape as shown by optical spectroscopy, high resolution mass spectrometry and X‐ray photoelectron spectroscopy. Optical spectroscopy and conductive atomic force microscopy reveal that these factors influence the near‐infrared absorbance and the electrical conductivity of the films. Consequently, the metal ion of the metalloporphyrin allows tuning of the macroscopic properties of the thin films composed of metalloporphyrin tapes.

Controlled formation of Schottky diodes on n-doped ZnO layers by deposition of p-conductive polymer layers with oxidative chemical vapor deposition

We report the controlled formation of organic/inorganic Schottky diodes by depositing poly(3,4-ethylenedioxythiophene) (PEDOT) on n-doped ZnO layers using oxidative chemical vapor deposition (oCVD). Current-voltage measurements reveal the formation of Schottky diodes that show good thermal and temporal stability with rectification ratios of 107 and ideality factors of ∼1.2. In the frame of a Schottky model, we identify a mean barrier height at the hybrid inorganic-organic interface of 1.28 eV, which is consistent with the difference between the work function of PEDOT and the electron affinity of ZnO. The findings highlight the strength of oCVD to design high-quality hybrid PEDOT/ZnO heterojunctions with possible applications in electronic and optoelectronic devices.

Mobility of Air-Stable p-type Polythiophene Field-Effect Transistors Fabricated Using Oxidative Chemical Vapor Deposition

Air-stable organic field-effect transistors (FETs) based on an unsubstituted polythiophene (PT) channel, processed using oxidative chemical vapor deposition (oCVD), have been investigated. The intrinsic properties of PT, including its rigid backbone structure and resistance to reactions with water and oxygen, lead to excellent air stability of oCVD PT-based FET devices. The effect of the channel/metalization contact resistance on the field-effect mobility (μFE) of PT-based FETs has also been investigated. Due to the channel/metallization contact resistance, the actual voltages applied to the channel are found to be significantly lower than the intended drain bias because of the voltage drops that occur at the source/drain contacts. Transmission-line measurements reveal that more than 30% of the intended drain bias is lost at all gate voltages applied to the channel. Reconstructed output characteristics excluding the contact effect allow the extraction of a corrected μFE, which is approximately 40% higher than that with contact resistance.

Linearity Improvement With AlGaN Polarization- Graded Field Effect Transistors With Low Pressure Chemical Vapor Deposition Grown SiNx Passivation

In this letter, we discuss the application of low pressure chemical vapor deposition (LPCVD) grown SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> passivation-first process to improve the power density and linearity performance of a metal oxide chemical vapor deposition (MOCVD) grown AlGaN channel polarization-graded field-effect transistor (PolFET). Significantly improved dispersion behavior was observed compared to plasma enhanced chemical vapor deposition (PECVD) grown SiN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> passivation. The Current collapse at 30 V drain quiescent condition for pulsed I-V was reduced to 8% (LPCVD) from 25% (PECVD). 10 GHz load-pull measurement showed a maximum output power density of 3.4 W/mm with a peak power added efficiency (PAE) of 40%. Two-tone intermodulation distortion measurement at 10 GHz for devices with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150\boldsymbol {\mu }\text{m}$ </tex-math></inline-formula> width revealed an OIP3 of 39 dBm and an excellent corresponding linearity figure of merit OIP3/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{P}_{{\textit {DC}}}$ </tex-math></inline-formula> of 13.3 dB. This is the best device level OIP3/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{P}_{{\textit {DC}}}$ </tex-math></inline-formula> reported to date at X-band for III-Nitride microwave transistors.

Tuning, optimization, and perovskite solar cell device integration of ultrathin poly(3,4-ethylene dioxythiophene) films via a single-step all-dry process.

For semicrystalline poly(3,4-ethylene dioxythiophene) (PEDOT), oxidative chemical vapor deposition (oCVD) enables systematic control over the b-axis lattice parameter (π-π stacking distance). Decreasing the b-axis lattice parameter increases the charge transfer integral, thus enhancing intracrystallite mobility. To reduce the barrier to intercrystallite transport, oCVD conditions were tailored to produce pure face-on crystallite orientation rather than the more common edge-on orientation. The face-on oriented oCVD PEDOT with the lowest b-axis lattice parameter displayed the highest in-plane electrical conductivity (σdc = 2800 S/cm), largest optical bandgap (2.9 eV), and lowest degree of disorder as characterized by the Urbach band edge energy. With the single step oCVD process at growth conditions compatible with direct deposition onto flexible plastic substrates, the ratio σdc/σop reached 50. As compared to spun-cast PEDOT:polystyrene sulfonate, integration of oCVD PEDOT as a hole transport layer (HTL) improved both the power conversion efficiency (PCE) and shelf-life stability of inverted perovskite solar cells (PSC).

Factors controlling conductivity of PEDOT deposited using oxidative chemical vapor deposition

This study is aimed to enhance the understanding of the processing-structure-property relationship in oxidative chemical vapor deposition (oCVD) conjugated polymers. Particular focus is made on the substrate and oxidant temperatures for the oCVD poly(3 4-ethylenedioxythiophene) (PEDOT) growth and their effects on the structure and electrical properties on resulting thin films. Doping levels are evaluated using Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy, which is complemented by Hall Effect investigations. Further, the relationship between doping level and conjugation length is described with discussion on mean free path, where the mean free path of oCVD PEDOT (up to ~5 nm) is significantly larger than typical organic semiconductors and comparable to conventional inorganic counterparts. The mechanisms that govern oCVD film growth are suggested, which is strongly dependent on both substrate and oxidant sublimation temperatures. Finally, the carrier transport behaviors, dominated by conjugation and doping levels are discussed.

Boron Nitride Nanotube Nucleation during Ni-Catalyzed Boron Oxide Chemical Vapor Deposition

Boron oxide chemical vapor deposition (BOCVD) has proved to be a valuable synthetic technique for the catalytic synthesis of boron nitride nanotubes (BNNTs) for almost two decades. However, the nuc...

Electronic surface, optical and electrical properties of p – GaN activated via in-situ MOCVD and ex-situ thermal annealing in InGaN/GaN LED

Electronic surface properties, optical and electrical characteristics of p-type Mg-doped Gallium Nitride (p-GaN) activated under different thermal annealing condition were investigated. In this work, p-GaN samples were subjected to in-situ and ex-situ thermal annealing process at 650 °C in Nitrogen (N2) rich condition. In-situ annealing process took place in Metal Oxide Chemical Vapor Deposition (MOCVD) chamber while ex-situ annealing process was carried out in the conventional oven. X-Ray and Ultraviolet Photoemission Spectroscopy (XPS/UPS) were used to observe the energy alignment of the p-GaN surface. From PES spectra, the sample subjected to in-situ thermal annealing shown to exhibit lower surface bend bending of 0.28 eV as compared to ex-situ thermal annealing activation with 0.45 eV band bending. This result is in agreement with specific contact resistance measurement that shows in-situ sample exhibits lower resistance resulted in better carrier injection from metal to p-GaN. Photoluminescence (PL) spectra elucidates that in-situ sample has a good surface quality with less nitrogen related vacancies (VN) formed on the p-GaN surface. All these results are further proved with the higher output power from LED with in-situ annealing. At 20 mA, in-situ sample shown an increment of ~14% light output power compared to ex-situ sample. Results obtained in this work suggest that the thermal activation condition for p-GaN activation process plays an active role on the surface quality as well as the energy alignment of the film surface and shows the potential of in-situ p-GaN activation for tunnel junction structure.

Low Reflection and Low Surface Recombination Rate Nano-Needle Texture Formed by Two-Step Etching for Solar Cells.

In this study, needle-like and pyramidal hybrid black silicon structures were prepared by performing metal-assisted chemical etching (MACE) on alkaline-etched silicon wafers. Effects of the MACE time on properties of the black silicon wafers were investigated. The experimental results showed that a minimal reflectance of 4.6% can be achieved at the MACE time of 9 min. The height of the nanostructures is below 500 nm, unlike the height of micrometers needed to reach the same level of reflectance for the black silicon on planar wafers. A stacked layer of silicon nitride (SiNx) grown by inductively-coupled plasma chemical vapor deposition (ICPCVD) and aluminum oxide (Al2O3) by spatial atomic layer deposition was deposited on the black silicon wafers for passivation and antireflection. The 3 min MACE etched black silicon wafer with a nanostructure height of less than 300 nm passivated by the SiNx/Al2O3 layer showed a low surface recombination rate of 43.6 cm/s. Further optimizing the thickness of ICPCVD-SiNx layer led to a reflectance of 1.4%. The hybrid black silicon with a small nanostructure size, low reflectance, and low surface recombination rate demonstrates great potential for applications in optoelectronic devices.

Oxidation of Monolayer WS2 in Ambient Is a Photoinduced Process.

We have studied the ambient air oxidation of chemical vapor deposition (CVD) grown monolayers of the semiconducting transition metal dichalcogenide (S-TMD) WS2 using optical microscopy, laser scanning confocal microscopy (LSCM), photoluminescence (PL) spectroscopy, and atomic force microscopy (AFM). Monolayer WS2 exposed to ambient conditions in the presence of light (typical laboratory ambient light for weeks or typical PL spectroscopy map) exhibits damage due to oxidation which can be detected with the LSCM and AFM, though may not be evident in conventional optical microscopy due to poorer contrast and resolution. Additionally, this oxidation was not random and was correlated with "high-symmetry" high intensity edges and red-shifted areas in the PL spectroscopy map, areas thought to contain a higher concentration of sulfur vacancies. In contrast, samples kept in ambient and darkness showed no signs of oxidation for up to 10 months. Low-irradiance/fluence experiments showed that samples subjected to excitation energies at or above the trion excitation energy (532 nm/2.33 eV and 660 nm/1.88 eV) oxidized in as little as 7 days, even for irradiances and fluences 8 and 4 orders of magnitude lower (respectively) than previously reported. No significant oxidation was observed for 760 nm/1.63 eV light exposure, which lies below the trion excitation energy in WS2. The strong wavelength dependence and apparent lack of irradiance dependence suggests that ambient oxidation of WS2 is initiated by photon-mediated electronic band transitions, that is, photo-oxidation. These findings have important implications for prior, present, and future studies concerning S-TMDs measured, stored, or manipulated in ambient conditions.

Molecular orbital studies of the initial process of gallium oxide chemical vapor deposition: micro-hydrolysis of triethylgallium

Gallium-doped zinc oxide films prepared by atomic layer deposition have received much attention. When triethylgallium is hydrolyzed on the surface of zinc hydroxide, a multi-layered metal oxide film containing a specific amount of gallium at a controlled position is formed. In this study, to elucidate the micro-hydrolysis mechanism of triethylgallium, reaction mechanisms involving one or two water molecules were investigated by molecular orbital calculations. The complete hydrolysis of triethylgallium occurs in three steps with the first partial hydrolysis being the rate limiting step. The activation energy of hydrolysis by two molecules of water is ∼10 kcal mol−1 lower than that with one molecule of water for all steps. The addition of further water molecules significantly decreases the activation energy because the transition state is stabilized by hydrogen bonding between the water molecules. These results suggest the hydrolysis reaction proceeds spontaneously under mild conditions by controlling the concentration of water molecules.

Reactivity of Nickel(II) Porphyrins in oCVD Processes-Polymerisation, Intramolecular Cyclisation and Chlorination.

Oxidative chemical vapour deposition of (5,15‐diphenylporphyrinato)nickel(II) (NiDPP) with iron(III) chloride as oxidant yielded a conjugated poly(metalloporphyrin) as a highly coloured thin film, which is potentially useful for optoelectronic applications. This study clarified the reactive sites of the porphyrin monomer NiDPP by HRMS, UV/Vis/NIR spectroscopy, cyclic voltammetry and EPR spectroscopy in combination with quantum chemical calculations. Unsubstituted meso positions are essential for successful polymerisation, as demonstrated by varying the porphyrin meso substituent pattern from di‐ to tri‐ and tetraphenyl substitution. DFT calculations support the proposed radical oxidative coupling mechanism and explain the regioselectivity of the C−C coupling processes. Depositing the conjugated polymer on glass slides and on thermoplastic transparent polyethylene naphthalate demonstrated the suitability of the porphyrin material for flexible optoelectronic devices.

Building ultraconformal protective layers on both secondary and primary particles of layered lithium transition metal oxide cathodes

Despite their relatively high capacity, layered lithium transition metal oxides suffer from crystal and interfacial structural instability under aggressive electrochemical and thermal driving forces, leading to rapid performance degradation and severe safety concerns. Here we report a transformative approach using an oxidative chemical vapour deposition technique to build a protective conductive polymer (poly(3,4-ethylenedioxythiophene)) skin on layered oxide cathode materials. The ultraconformal poly(3,4-ethylenedioxythiophene) skin facilitates the transport of lithium ions and electrons, significantly suppresses the undesired layered to spinel/rock-salt phase transformation and the associated oxygen loss, mitigates intergranular and intragranular mechanical cracking, and effectively stabilizes the cathode–electrolyte interface. This approach remarkably enhances the capacity and thermal stability under high-voltage operation. Building a protective skin at both secondary and primary particle levels of layered oxides offers a promising design strategy for Ni-rich cathodes towards high-energy, long-life and safe lithium-ion batteries. Intensive research efforts are underway to enable applications of layered lithium transition metal oxides in batteries. Here the authors report an oxidative chemical vapour deposition technique to conformally coat both the primary and the secondary particles of these oxides to unleash potential applications.

Microstructure-dependent electrochemical properties of chemical-vapor deposited poly(3,4-ethylenedioxythiophene) (PEDOT) films

Conductive polymer electrodes hold exceptional promise in energy conversion technologies and bioelectronics due to the inherent mechanical flexibility and synthetic tunability of physical, chemical, and electronic properties. Solution-processing is favorable to retain low-cost but can often result in heterogeneity of physical and electronic structure due to non-conjugated side chains and polyionic dopants creating insulating domains. Such a complex landscape limits control and systematic understanding of fundamental properties including electrical and ionic transport and rates of electron transfer central to overall device efficiencies. Oxidative chemical vapor deposition (oCVD) offers a promising route to simultaneously synthesize and deposit conductive polymer films at low temperatures (<150°C) with controllable microstructure. Herein we use the oCVD technique to synthesize and deposit different paracrystalline films of poly(3,4-ethylenedioxythiophene). Using grazing incidence wide-angle x-ray scattering, we demonstrate three different orientations of the π-π packing direction, relative to the surface normal, to yield thin films with face-on, edge-on, and isotropic character. These different microstructures have direct impact on the electrochemical conditioning of the redox properties of the films. We show that electrochemical properties, as defined by energy and power density, are highest for crystalline materials with edge-on orientation to facilitate ion transport while still retaining reasonable electrical conductivity.

Gas Phase Synthesis and Deposition of Directly Fused Porphyrin Tapes: Reaction Mechanism and Central Metal Ion Effect.

The formation of directly fused porphyrin tapes attracted the interest of the scientific community because of their electronic and optical properties such as extremely low bandgap, NIR and two photon absorption. The synthesis of these compounds is tedious because of their low solubility and require the introduction of solubilizing substituents adding further synthetic efforts.[1] Moreover, these materials are hard to process and integrate into device while the solubilizing substituents hinder the π­-π interactions affecting the properties of the resulting materials.[1],[2] These drawbacks were circumvented with the oxidative Chemical Vapour Deposition (oCVD) of phenyl meso-substituted porphyrins, which allowed to achieve in a single step the synthesis, deposition and doping of polymeric fused porphyrins tapes thin films from commercially available chemicals.[2] Our approach allows the deposition of patterned films and is compatible with sensitive substrates such as paper or polymers (Figure 1a). Using Ni(II) 5,15–(diphenyl) porphyrin (NiDPP), 5,10,15–(triphenyl) porphyrin (NiP3P) and 5,10,15,20–(tetraphenyl) porphyrin (NiTPP), we elucidate the reaction active sites, the side reactions (Figure 1b) and the differences to solution based approaches via high resolution mass spectrometry, UV-Vis-NIR spectroscopy, electron paramagnetic resonance (EPR) and Density Functional Theory (DFT). We also investigate the effect of the central metal ion on the direct fusion reaction of Fe(III)Cl, Co(II), Ni(II), Cu(II), Pd(II), H2 and Zn(II), 5,15–(diphenyl) porphyrins in oCVD. Furthermore, the electrical, electronic and morphological properties of the prepared thin films were thoroughly investigated by means of X-ray Photoelectron Spectroscopy (XPS), Helium Ion Microscopy (HIM) and Conductive Atomic Force Microscopy (C-AFM). [1] T. Tanaka, A. Osuka – Conjugated porphyrin arrays: synthesis, properties and applications for functional materials – Chem Soc Rev. 2015, 44, 943. [2] G. Bengasi, K. Baba, G. Frache, P. Gratia, K. Heinze, N. D. Boscher – Conductive Fused Porphyrin Tapes on Sensitive Substrates by a Chemical Vapor Deposition Approach – Angew. Chem. Int. Ed. 2018, DOI: 10.1002/anie.201814034. Figure 1) a) The chemical vapour deposition reaction of NiDPP and FeCl3 yields a homogeneous and conductive coating also on sensitive and bendable substrates which evidences the suitability for modern optoelectronic devices. b) Reaction schemes for the CVD reaction of NiDPP and FeCl3 and side reactions observed during the deposition (chlorination, cyclization of the phenyl ring). Figure 1