Function Of Substrate Temperature Research Articles

Effects of the incorporation of copper on the micro structure, charge transport and photoelectrical properties of sputtered ZnTe:Cu films

Advances in solar cell technology require improving the relevant physical properties of the constituent materials. One important functionality in photovoltaic devices is the efficient charge transport through the cell. Copper-doped zinc telluride (ZnTe:Cu) has been used as contact to cadmium telluride, the light-absorbing layer in photovoltaic devices. Out of the various deposition techniques, radio frequency sputtering is one of the most versatile and widely employed in research laboratories and industry. In this work, is presented a thorough characterization of ZnTe and ZnTe:Cu films grown by sputtering as a function of substrate temperature (Ts = 300 and 350 °C) and copper concentration (1, 3 and 5 at%). Besides the structural (X-ray diffraction), optical (UV-Vis spectroscopy) and electrical (Hall effect) characterizations, the present study included other studies relevant for optoelectronic applications such as photoluminescence, photoconductivity (under constant or transient illumination) and, in order to determine the effect of copper on the work function, Kelvin probe force microscopy was applied to the samples. Our results show important improvements in crystallite size, conductivity and photoconducting properties derived from the incorporation of copper in the ZnTe lattice.

Investigation of microstructural and mechanical properties of sputter-deposited Ni3Al films at different substrate temperatures

Ni3Al films were deposited on silicon (100) substrate at different substrate temperatures by DC magnetron sputtering. The evolution of phase, microstructure, surface topography and mechanical properties have been investigated as a function of substrate temperature via XRD, FE-SEM, AFM and nanoindentation respectively. Results revealed that the deposited film possessed the preferred orientation of (111) whereas the crystallite size increased and grain size decreased with increase in the substrate temperature. The results of nanoindentation showed that the hardness of the film increased up to 400 °C after which it abruptly decreased. Maximum hardness of ∼13 GPa was achieved when the film was deposited at the substrate temperature of 400 °C. The surface roughness of the film increases simultaneously with the increase in substrate temperature whereas the static contact angle and mechanical properties declined significantly for the film deposited at the substrate temperature of 600 °C. This study reflects the impact of substrate temperature on the evolution of phase, microstructure and mechanical properties of Ni3Al coatings deposited at different substrate temperatures.

Investigations on temperature dependent properties of spray deposited tin oxide thin films

The present study reported the temperature dependent properties of tin oxide (SnO2) thin films deposited by using conventional, cost effective and non-vacuum-based spray pyrolysis technique (SPT). The as deposited films were characterized by various characterization techniques such as X ray diffraction (XRD), UV-Vis spectroscopy and Scanning electron microscopy (SEM) to study their structural, optical and morphological properties respectively. XRD analysis revealed tetragonal rutile crystal structure of SnO2 with preferred orientation along (200) plane. The refinement of XRD data was also carried out by Rietveld refinement to obtain the fitting parameters, crystallite size and lattice parameters. UV-Vis study showed considerable change in optical absorbance and transmittance with change in substrate temperature. Effect of substrate temperature on film thickness, refractive index and band gap energy were determined by Swanepoel method and by Tauc’s plot respectively. The Urbach energy was also calculated and were correlated to the defects in SnO2 films. SEM micrograph showed the transformation from granules to nanospheres as a function of substrate temperature. Electrical properties were determined by Hall effect measurements which gives carrier concentration, electrical resistivity and mobility in the order of 1019-1020 /cm3, 10−2-10−3 Ω.cm and 4–23 cm2/Vs respectively.

Sn-mediated transformations on Si(111) surface: Reconstructions, Electromigration, Homoepitaxy

We have studied Si mass transport and morphological transformations on the Si(111) surface during (√3 × √3)-Sn reconstruction formation and following Si homoepitaxy in 600–825°C interval by in situ ultrahigh vacuum reflection electron microscopy (UHV REM) and ex situ atomic force microscopy (AFM). We have shown that the formation of a metallic α-(√3 × √3)-Sn phase during Sn deposition at T < 650 °С leads to Si 2D island nucleation on > 1 μm terraces, while the formation of a mosaic γ-(√3 × √3)-Sn phase at T > 650 °С is followed by monatomic step shift in the step-up direction and provides Sn/Si(111) interface with wide atomically flat terraces. The step shift value has been measured as functions of substrate temperature and Sn deposition rate to determine emitted by the steps Si coverage participating in γ-phase formation. The electromigration-induced drift of disordered “1 × 1”-Sn domains has been shown to entail enhanced noncompensated Si mass transport followed by the Si(111)-(√3 × √3)-Sn surface roughening. The kinetics of 2D island nucleation and growth near monatomic steps and on wide (up to 10 μm) terraces on the Si(111)-γ-(√3 × √3)-Sn surface during Si deposition at 700°C is limited by surface diffusion only, and critical nucleus i consists of ∼ 20–100 Si atoms.

Preparation of GaN/Porous silicon heterojunction photodetector by laser deposition technique

In this work, gallium nitride (GaN) thin film was deposited on porous silicon (PSi) substrate via a pulsed laser deposition route with a 355 nm laser wavelength, 900 mJ of laser energy, and various substrate temperatures raging from 200 to 400 °C. The structural and optical properties of GaN films as a function of substrate temperature are investigate. XRD studies reveal that the GaN films deposited on porous silicon are nanocrystalline with a hexagonal wurtzite structure along (002) plane. The photoluminescence emission peaks of the GaN/PSi prepared at 300 °C substrate temperature are located at 368 nm and 728 nm corresponding to energy gap of 3.36 eV and 1.7 eV, respectively. The GaN/PSi heterojunction photodetector prepared at 300 °C exhibits the maximum performance, with a responsivity of 29.03 AW−1, detectivity of 8.6 × 1012 Jones, and an external quantum efficiency of 97.2% at 370 nm. Similarly, at 575 nm, the responsivity is 19.86 AW−1, detectivity is 8.9 × 1012 Jones, and the external quantum efficiency is 50.89%. Furthermore, the photodetector prepared at a temperature of 300 °C demonstrates a switching characteristic where the rise time and fall time are measured to be 363 and 711 μs, respectively.

High crystalline epitaxial thin films of NiO by plasma-enhanced ALD and their properties

NiO is an interesting transition metal oxide due to its fascinating properties. High crystalline thin films of NiO are preferred for use in a variety of device applications but are challenging to deposit at low temperatures. We have prepared epitaxial thin films of NiO with [111] as the preferred growth direction on a c-plane sapphire substrate at relatively low temperatures using plasma-enhanced atomic layer deposition (PEALD) exploiting a simple nickel precursor with oxygen plasma. The evolution of crystallinity and surface morphology of the films were studied as a function of substrate temperature. Ultra-smooth NiO films with excellent crystallinity were prepared at 250 °C without the necessity for post-annealing. Different microscopic and spectroscopic methods revealed film characteristics. The magnetic properties of (111) oriented epitaxial NiO films prepared using PEALD are explored for the first time, and they are antiferromagnetic in nature.

Effect of deposition temperature on topography and electrochemical water oxidation of NiO thin films

The deposition temperature plays a significant role in controlling the crystallinity, morphology, and texture of thin films. Herein, we report the fabrication of nickel oxide thin films on a fluorine-doped tin oxide-coated glass substrate via a single-step aerosol-assisted chemical vapor deposition technique. Variable temperatures from 450 to 525 °C were used for the fabrication of these NiO thin films. The crystalline structure of nickel oxide thin films was determined by X-ray diffraction which showed cubic structure having space group Fm3m, and unit cell lattice parameters of a = b = c = 4.17 Å that crystallize preferentially along (200) plane. While the Raman spectroscopic study revealed the presence of peaks corresponding to nickel oxide structure. The surface chemical composition and oxidation states were investigated by X-ray photoelectron spectroscopy. Moreover, field-emission scanning electron microscopy aided in examining the temperature-dependent topography and microstructure of films. It was observed that when deposition temperature is increased from 450 to 525 °C, the bandgap energy decreased from 3.59 to 3.41 eV. The electrocatalytic activity for the oxygen evolution reaction was performed under alkaline conditions, using linear sweep voltammetry and cyclic voltammetry at different scan rates. Moreover, ohmic drop and charge transfer resistance are estimated by electrochemical impedance spectroscopy. The nickel oxide deposited at 500 °C showed the highest current density and the earliest onset overpotential as compared with other samples at different temperatures. Morphology-dependent catalytic activity is attributed to substrate temperature which significantly affects the growth of nickel oxide. Cyclic voltammetry reveals the Ni redox feature due to the active phase of nickel (oxy)hydroxide (NiOOH) and there was no significant current until 1.5 VRHE. Measurements of activity as a function of substrate temperature were consistent with the hypothesis that different morphology of the electrode exerts different charge transfer activation on nickel oxide. These results suggested that electrocatalysts coupled with controlled morphology can be tuned in terms of high performance, commercial applicability, and water-splitting devices.

Controlling the size and density of InN quantum dots formed on sapphire substrate by droplet epitaxy

The growth of InN quantum dots (QDs) on c-plane sapphire by droplet epitaxy (DE) using radio frequency plasma-assisted molecular beam epitaxy is reported here. The QD growth process from liquid In droplets to the InN QDs is described with a focus on the effect ambient nitrogen from an active RF-plasma source has on the formation of In droplets as a function of substrate temperatures. The variation in the shape and size of InN QDs is explained in terms of the In atom surface diffusion and the migration of droplets. Additionally, two nitridation procedures were used to investigate the crystallization of In droplets. The droplet formation was determined to follow well known principles of nucleation theory with ripening. The resulting activation energy for In surface diffusion on sapphire was found to be 0.62 ± 0.07 eV in ultra-high vacuum, ∼10−10 Torr, and 0.57 ± 0.08 eV in ambient N2, ∼10−5 Torr. The growth of InN QDs using the DE method has many advantages over the classical Stranski–Krastanov technique, including the ability to control a wide range of QD shapes, sizes, and densities.

Comparative research fluorine and colloidal aggregate formation on the surface lithium fluoride thin films during electronic, ionic and thermal treatments

In this study, we present the results of our investigation of fluorine and colloidal aggregate formation in the LiF/Si(111) system as a function of substrate temperature and electron and ion beams. Excitons generated by electron or ion irradiation will form a stable F-H pair, which subsequently forms aggregate centres before their coalescence into fluoride and colloidal macromolecules. Additionally, after annealing the LiF film, colloids and anionic complexes are formed on the surface. The experimental data show the formation of colloids after 5 min of annealing at a temperature of 75 °C. Furthermore, when the LiF films annealed at a temperature of 400 °C, chemical reactions on the surface, such as the formation of silicide, are excited. The obtained experimental data show that an increase in the target temperature during the formation of primary point defects and their association can be represented by the migration of their components on the surface.

Epitaxial synthesis of unintentionally doped p-type SnO (001) via suboxide molecular beam epitaxy

By employing a mixed SnO2 + Sn source, we demonstrate suboxide molecular beam epitaxy (S-MBE) growth of phase-pure single-crystalline metastable SnO (001) thin films on Y-stabilized ZrO2 (001) substrates at a growth rate of ∼1.0 nm/min without the need for additional oxygen. These films grow epitaxially across a wide substrate temperature range from 150 to 450 °C. Hence, we present an alternative pathway to overcome the limitations of high Sn or SnO2 cell temperatures and narrow growth windows encountered in previous MBE growth of metastable SnO. In situ laser reflectometry and line-of-sight quadrupole mass spectrometry were used to investigate the rate of SnO desorption as a function of substrate temperature. While SnO ad-molecule desorption at TS = 450 °C was growth-rate limiting, the SnO films did not desorb at this temperature after growth in vacuum. The SnO (001) thin films are transparent and unintentionally p-type doped, with hole concentrations and mobilities in the range of 0.9–6.0 × 1018 cm−3 and 2.0–5.5 cm2 V−1 s−1, respectively. These p-type SnO films obtained at low substrate temperatures are promising for back-end-of-line (BEOL) compatible applications and for integration with n-type oxides in pn heterojunctions and field-effect transistors.

Structural transitions on Si(1 1 1) surface during Sn adsorption, electromigration, and desorption studied by in situ UHV REM

Using in situ ultrahigh vacuum reflection electron microscopy, we have studied structural transitions on the Si(111) surface induced by Sn deposition up to 2 ML coverage (1 ML = 7.8∙1014 cm−2) and by Sn desorption at substrate temperatures T = 200–860 °C. We have shown that Si–Sn intermixing in the adsorption layer during Sn deposition onto the Si(111)-(7 × 7) surface at T > 650 °C leads to the shift of the monatomic steps in the step-up direction, and there is formed a mosaic (√3×√3)-Sn phase. The electromigration of Sn adatoms induced by DC resistive heating has been shown to redistribute adsorbed Sn layer and to cause local (√3×√3)-Sn ⇔ “1 × 1”-Sn structural transitions on the surface. We have estimated the lower bound of the Sn adatom positive effective charge on the Si(111) surface qeffSn ≥ 0.001∙e. During AC annealing, the rate of desorption-induced “1 × 1”-Sn domain area shrinkage has been measured as a function of substrate temperature, and the activation energy of Sn adatom desorption has been estimated to be 2.5 ± 0.1 eV.

Effect of sputtering power and substrate temperature on structural, optical, wettability and anti-icing characteristics of aluminium doped zinc oxide

Thin films of ZnO:Al were synthesized on glass substrates by RF magnetron sputtering. Structural, optical, wettability and anti-icing properties of the thin films are studied as a function of substrate temperature and sputtering power. XRD patterns showed an increase in the intensity of (002) peak when the sputtering power and substrate temperature are increased. The roughness and average grain size also increased with an increment in substrate temperature and sputtering power. Transmittance and band gap energy observed in the wavelength range of 350–800 showed the average transmittance was in the range of 90 to 76% and 3.12–2.88 eV. The contact angle and anti-icing properties observed during the investigation demonstrated that the synthesized coatings are hydrophobic and the formation of ice was delayed when compared to uncoated substrates.

Transition metal dichalcogenide graded alloy monolayers by chemical vapor deposition and comparison to 2D Ising model

In this work, a chemical vapor deposition (CVD) method was developed for the synthesis of transition metal dichalcogenide alloy monolayers, with a composition gradient in the radial direction. The composition gradient was achieved by controlling the substrate cooling rate during the CVD growth. The two types of alloys, namely, WS2(1-x)Se2x and MoS2(1-x)Se2x, were found to exhibit an opposite composition gradient. This is attributed to their different cohesive energies. A two-dimensional Ising model is used to explain the growth mechanism, where two ends of the composition were modeled as a magnetically ordered phase and a paramagnetic phase. The composition as a function of substrate temperature is then represented by the thermal magnetization curve.

Effects of atomic oxygen on the growth of NiO films by reactive magnetron sputtering deposition

Reactive sputtering deposition has been widely applied to the preparation of oxide films, but a method is still needed to stably control the deposition process and the film growth. In this work, the plasma in the vicinity of sputtering target is studied by optical emission spectroscopy and the atomic oxygen density ([O]) is linked to the sputtering mode and the growth of NiO films. The NiO films can be deposited either in oxide mode or in the transition region, whereas the [O] value plays an important role in determining the growth behavior of NiO films and the crystallinity. In the transition region, the (111)-oriented growth of NiO films is preferential and the crytallinity is improved with the decrease in the [O] value. In the oxide mode, the NiO films are preferentially (001)-oriented and exhibit a relatively good crystallinity. By fixing the O2/Ar flow ratio at a constant, the [O] value is explored as a function of substrate temperature, showing that the oxygen desorption may have significant impacts on the [O] value as the substrate temperature is higher than 400 °C.

Nitrogen-Incorporated Boron-Doped Nanocrystalline Diamond Nanowires for Microplasma Illumination.

The origin of nitrogen-incorporated boron-doped nanocrystalline diamond (NB-NCD) nanowires as a function of substrate temperature (Ts) in H2/CH4/B2H6/N2 reactant gases is systematically addressed. Because of Ts, there is a drastic modification in the dimensional structure and microstructure and hence in the several properties of the NB-NCD films. The NB-NCD films grown at low Ts (400 °C) contain faceted diamond grains. The morphology changes to nanosized diamond grains for NB-NCD films grown at 550 °C (or 700 °C). Interestingly, the NB-NCD films grown at 850 °C possess one-dimensional nanowire-like morphological grains. These nanowire-like NB-NCD films possess the co-existence of the sp3-diamond phase and the sp2-graphitic phase, where diamond nanowires are surrounded by sp2-graphitic phases at grain boundaries. The optical emission spectroscopy studies stated that the CN, BH, and C2 species in the plasma are the main factors for the origin of nanowire-like conducting diamond grains and the materialization of graphitic phases at the grain boundaries. Moreover, conductive atomic force microscopy studies reveal that the NB-NCD films grown at 850 °C show a large number of emission sites from the grains and the grain boundaries. While boron doping improved the electrical conductivity of the NCD grains, the nitrogen incorporation eased the generation of graphitic phases at the grain boundaries that afford conducting channels for the electrons, thus achieving a high electrical conductivity for the NB-NCD films grown at 850 °C. The microplasma devices using these nanowire-like NB-NCD films as cathodes display superior plasma illumination properties with a threshold field of 3300 V/μm and plasma current density of 1.04 mA/cm2 with a supplied voltage of 520 V and a lifetime stability of 520 min. The outstanding plasma illumination characteristics of these conducting nanowire-like NB-NCD films make them appropriate as cathodes and pave the way for the utilization of these materials in various microplasma device applications.

Anti-reflection for monocrystalline silicon from diamond-like carbon films deposited by magnetron sputtering

In this work, diamond-like carbon (DLC) films used as anti-reflective coatings for monocrystalline silicon were deposited by magnetron sputtering for potential application in solar cells. The microstructural and optical properties of the films were investigated as a function of substrate temperature over a wide range during deposition. It showed that, when the substrate temperature increased from RT to 800 °C, the hybridized structures of the DLC films accordingly changed associated with a significant variation of refractive index between2.22 and 1.64 at a wavelength of 550 nm. Three types of coating systems, namely single-, three- and five-layer films on monocrystalline silicon substrates, were designed based on the anti-reflection principle and fabricated in terms of the relationships of refractive index and deposition rate with substrate temperature. In particular, a well-designed three-layer film, of which the refractive index gradually changed along the thickness, that is 1.8, 1.9 and 2.0, respectively, was successfully deposited at one step on monocrystalline silicon substrates by adjusting substrate temperature and deposition time, and featured a broadband anti-reflective characteristic with low average reflectivity of 8.7% at a wide solar spectrum of 400–1100 nm. This work demonstrates that the DLC film has a promising application potential as broadband anti-reflective coatings in silicon-based solar cells.

Nanoindentation and Photoluminescence Studies of Hydrogenated Boron Carbon Nitride Thin Films

Nanoindentation and photoluminescence (PL) studies were performed on hydrogenated boron carbon nitride thin films deposited using radio frequency magnetron sputtering. Dual target sputtering from B4C and BN targets was used to deposit films. The variation in the composition of films was studied using energy-dispersive X-ray spectroscopy. The influence of hydrogen gas and substrate temperature on the mechanical properties was investigated using nanoindentation measurements. Photoluminescence studies were performed on films deposited under varying hydrogen content and different deposition temperatures. The films deposited in this study exhibited hardness of 6–22 GPa and Young’s modulus of 125–140 GPa. PL spectra demonstrated two prominent emission peaks around 499 nm and 602 nm for the deposited films. Increasing the hydrogen gas ratio in the films induced PL peak shifts to longer wavelengths. Emission spectra shifted to long wavelength with increasing substrate temperature. The emission peak position shifted from 499 nm to 544 nm and from 602 nm to 655 nm as a function of substrate temperature. For the first time, BCNH based thin films PL behavior at low temperature (77 K) has been characterized in this study. The BCNH thin films show a rare phenomenon of negative thermal quenching of emission.

Effects of substrate temperature on patterns produced by dried droplets of proteins

Rapid diagnosis provides better clinical management of patients, helps control possible outbreaks, and increases survival. The study of deposits produced by the evaporation of droplets is a useful tool in the diagnosis of some health problems. With the aim to improve diagnostic time in clinical practice where we use the evaporation of droplets, we explored the effects of substrate temperature on pattern formation of dried droplets in globular protein solutions. Three deposit groups were observed: “functional” patterns (from 25 to 37 ∘C), “transition” patterns (from 44 to 50 ∘C), and “eye” patterns (from 58 to 63 ∘C). The dried droplets of the first two groups show a ring structure (“coffee-ring”) that confines a great diversity of aggregates such as needle-like structures, tiny blade-shape crystals, highly symmetrical crystallization patterns, and amorphous salt aggregates. In contrast, the “eye” patterns are deposits with a large inner aggregate surrounded by a coffee ring, and they can appear from the evaporation of droplets in protein binary mixtures and blood serum. Interestingly, the unfolding proteins correlates with the formation of “eye” patterns. We measured stain diameter, “coffee-ring” thickness, radial density profile, and entropy computed by GLCM-statistics to quantify the structural differences among deposit groups. We found that “functional” patterns are structurally indistinguishable among them, but they are clearly different from elements of the other deposit groups. An exponential decay function describes pattern formation time as a function of substrate temperature, which is independent from protein concentration. Patterns formation at 32 ∘C takes place up to 63% less time and preserves the structural characteristics of dried droplets in proteins formed at room temperature. Therefore, we argue that droplet evaporation at this substrate temperature could be an excellent candidate to make a more efficient diagnosis based on droplet evaporation of biofluids.

In situ ellipsometry monitoring of TiO[formula omitted] atomic layer deposition from Tetrakis(dimethylamido)titanium(IV) and H[formula omitted]O precursors on Si and In[formula omitted]Ga[formula omitted]As substrates

TiO2 Atomic Layer Deposition (ALD) is used in microelectronics due to its ability to produce conformal thin films whose thickness is controlled at the sub-nanometer scale. Tetrakis(dimethylamido)titanium(IV) and water are frequently used precursors for TiO2 ALD, although there are still some differences in growth behavior in the literature. In this parametric study, the growth of TiO2 was controlled in situ by Multi-Wavelength Ellipsometry in combination with ex situ thickness measurements by X-ray Reflectometry. The injection and purge times were optimized to reach self-saturation on the surface. We put in evidence two regions of the Growth Per Cycle (GPC) as a function of substrate temperature: GPC decreases from 0.8 Å cy−1 to 0.5 Å cy−1 as the temperature rises from 50 °C to 200 °C, and then GPC increases from 0.6 Å cy−1 to 0.9 Å cy−1 as the temperature rises from 250 °C to 350 °C. There is no evidence of an ALD window - the temperature region where the growth rate is the same. The stoichiometry of the layer grown at 200 °C, determined by X-ray Photoelectron Spectroscopy, is TiO2 (1 Ti atom per 2 O atoms). The 200 °C as-grown sample becomes crystalline (Anatase crystals) after annealing 3 h in air at 400 °C, or at 600 °C. The initial growth stages of TiO2 were studied by Multi-Wavelength Ellipsometry and Atomic Force Microscopy. Regarding TiO2 ALD on (100)Si substrate (with a native SiO2), we observed a substrate enhanced growth which turned into steady-state ALD beyond 20–30 cycles. Additionally, TiO2 ALD on (001)In0.53Ga0.47As substrate demonstrates substrate inhibited growth of type 2 (islands formation) which turned into TiO2 steady-state ALD beyond 20–30 cycles. The results of TiO2 ALD are compared with those of the existing literature.

Real-time in situ process monitoring and characterization of GaN films grown on Si (100) by low-temperature hollow-cathode plasma-atomic layer deposition using trimethylgallium and N2/H2 plasma

In this work, we report on the in situ process monitoring and materials characterization of low-temperature self-limiting grown gallium nitride (GaN) thin films. GaN samples were synthesized on Si (100) substrates via remote hollow-cathode plasma-atomic layer deposition (HCP-ALD) using trimethylgallium and N2/H2 plasma as a metal precursor and a nitrogen coreactant, respectively. A multiwavelength in situ ellipsometer was employed to monitor the saturating surface reactions and determine the self-limiting growth conditions. The subangstrom thickness resolution of ellipsometry enabled the real-time observation of single chemical adsorption and plasma-induced ligand removal/exchange events. Taking advantage of this in situ capability, saturation experiments have been carried out within the 120–240 °C temperature range without interruption featuring 10-cycle subruns for each parameter change. Plasma power, plasma exposure duration, and plasma chemistry (gas composition) are the main process parameters that have been investigated. Ex situ optical, structural, and chemical characterization is carried out on 600-cycle HCP-ALD-grown GaN films as a function of substrate temperature. Hexagonal single-phase polycrystalline GaN films with (002) preferred orientation was obtained at substrate temperatures higher than 200 °C. The crystalline GaN films exhibited below-detection-limit carbon content and slightly gallium rich stoichiometry. Substrate temperature and plasma power played a critical role on GaN film properties with 200 °C and 150 W as threshold values for crystallization. Moreover, we observed that Ar-free N2/H2 plasma gas composition led to a slightly stronger (002) dominant crystal orientation.