Crystalline Volume Fraction Research Articles

Activation energy study of intrinsic microcrystalline silicon thin film prepared by VHF-PECVD

Intrinsic microcrystalline silicon thin film were prepared by VHF-PECVD, the activation energy of thin film were measured by activation energy testing equipment. The activation energy of samples with different crystalline volume fraction and prepared at different power and different pressure were studied. The results showed that: the activation energy of samples deposited at amorphous/microcrystalline transition zone decrease as crystalline volume fraction increasing. With increasing of depositing power and pressure, the depositing rate were increased, the activation energy were also increased, the oxygen contaminate could be suppressed by increasing depositing rate by increasing depositing power and pressure.

The Synthesis and Structural Properties of Crystalline Silicon Quantum Dots upon Thermal Annealing of Hydrogenated Amorphous Si-Rich Silicon Carbide Films

Silicon quantum dots (QDs) embedded in non-stoichiometric hydrogenated silicon carbide (SiC:H) thin films have been successfully synthesized by plasma-enhanced chemical vapor deposition and post-annealing. The chemical composition analyses have been carried out by x-ray photoelectron spectroscopy (XPS). The bonding configurations have been deduced from Fourier transform infrared absorption measurements (FTIR). The evolution of microstructure with temperature has been characterized by glancing incident x-ray diffraction (XRD) and Raman diffraction spectroscopy. XPS and FTIR show that it is in Si-rich feature and there are a few hydrogenated silicon clusters in the as-grown sample. XRD and Raman diffraction spectroscopy show that it is in amorphous for the as-grown sample, while crystalline silicon QDs have been synthesized in the 900°C annealed sample. Silicon atoms precipitation from the SiC matrix or silicon phase transition from amorphous SiC is enhanced with annealing temperature increase. The average sizes of silicon QDs are about 5.1 nm and 5.6 nm, the number densities are as high as 1.7 × 1012 cm−2 and 3.2 × 1012 cm−2, and the crystalline volume fractions are about 58.3% and 61.3% for the 900°C and 1050°C annealed samples, respectively. These structural properties analyses provide an understanding about the synthesis of silicon QDs upon thermal annealing for applications in next generation optoelectronic and photovoltaic devices.

Mechanical properties by instrumented indentation of solution precursor plasma sprayed hydroxyapatite coatings: Analysis of microstructural effect

The mechanical properties of solution precursor plasma sprayed hydroxyapatite (SPPS-HA) coatings were investigated by instrumented indentation test in relation to their microstructural characteristics. The morphology of the coatings using solution that is more concentrated shows cauliflower-like surface with fine particles and agglomerated fragmented shells while dome-like formations with spherical particles around were observed for coatings from less concentrated solution. The coatings had elastic modulus and hardness values in the range of 5.0 to 22.0 GPa and 0.04 to 0.17 GPa, respectively. The strong disparities in elastic modulus and hardness values were attributed mainly to the morphology and crystallinity of the coatings. The coatings prepared from more concentrated solution precursors had average elastic modulus and hardness nearly two times greater than the coatings prepared from solution of low concentration. Variation of hardness values was due to the densification of the coating material upon indentation. Models employed enabled to describe the hardness and elastic modulus of coatings as a function of crystallinity volume fraction. Moreover, for the HA coatings to exhibit bone-like microstructure, it was found that the crystallinity volume fraction should be within 0.56–0.86.

An amorphous-to-crystalline phase transition within thin silicon films grown through ultra-high-vacuum evaporation on fused quartz substrates

ABSTRACTA number of thin silicon films are prepared through ultra-high-vacuum evaporation on optical quality fused quartz substrates with different growth temperatures. Through an analysis of grazing incidence X-ray diffraction results, a phase transition, from amorphous-to-crystalline, is found corresponding to increases in the growth temperature. The corresponding Raman spectra are also observed to change their form as the films go through this phase transition. Using a Raman peak decomposition process, this phase transition is then quantitatively characterized through the determination of the amount of intermediate-range order and the crystalline volume fraction for the various growth temperatures considered in this analysis. The possible device consequences of these results are then commented upon.

Microstructure and lateral conductivity control of hydrogenated nanocrystalline silicon oxide and its application in a-Si:H/a-SiGe:H tandem solar cells**Project supported by the Hi-Tech Research and Development Program of China (Grant No. 2013AA050302), the National Natural Science Foundation of China (Grant No. 61474065), Tianjin Municipal Research Key Program of Application Foundation and Advanced Technology, China (Grant No. 15JCZDJC31300), the Key Project in

Phosphorous-doped hydrogenated nanocrystalline silicon oxide (n-nc-SiOx:H) films are prepared via radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). Increasing deposition power during n-nc-SiOx:H film growth process can enhance the formation of nanocrystalline and obtain a uniform microstructure of n-nc-SiOx:H film. In addition, in 20s interval before increasing the deposition power, high density small grains are formed in amorphous SiOx matrix with higher crystalline volume fraction (Ic) and have a lower lateral conductivity. This uniform microstructure indicates that the higher Ic can leads to better vertical conductivity, lower refractive index, wider optical band-gap. It improves the back reflection in a-Si:H/a-SiGe:H tandem solar cells acting as an n-nc-SiOx:H back reflector prepared by the gradient power during deposition. Compared with the sample with SiOx back reflector, with a constant power used in deposition process, the sample with gradient power SiOx back reflector can enhance the total short-circuit current density (Jsc) and the initial efficiency of a-Si:H/a-SiGe:H tandem solar cells by 8.3% and 15.5%, respectively.

Multi-layered hydrogenated p-type microcrystalline silicon windows for a-Si:H thin film solar cells on opaque substrates

The effects of multi-layered p-type microcrystalline (μc-) Si:H windows on the performance of substrate-type amorphous Si:H thin film solar cells on opaque substrates were investigated. The results were well explained in terms of H2-plasma-induced damage (HPID) at the p/i-interface and the near-interface region of the light-absorbing layer. The μc-Si:H was deposited using plasma enhanced chemical vapor deposition in a H2-rich atmosphere. A high microcrystalline volume fraction was obtained with a high H2 dilution ratio, which can cause considerable HPID. Cell efficiency was enhanced with a multi-layered p-type μc-Si:H composed of films with low and high crystalline volume fraction, compared to cells with single-layered μc-Si:H. In the multi-layered p-type μc-Si:H, the low crystalline film was placed on an i-Si:H layer to reduce HPID. The present work demonstrated that HPID was reduced at the p/i-interface and the near-interface region of the light-absorbing layer, and that the quality of the p-type μc-Si:H needs to be a significant consideration to achieve high efficiency.

Non-uniform distribution in µc-Si1−xGex:H and its influence on thin film and device performance

In this work, hydrogenated microcrystalline silicon germanium (µc-Si1−xGex:H) thin films were fabricated by plasma-enhanced chemical vapor deposition (PECVD) and developed as the infrared absorber for thin film silicon solar cells. Three kinds of the non-uniform distribution in µc-Si1−xGex:H thin films including: “the non-uniform distribution of Si and Ge”, the non-uniform distribution of crystallization”, and “the non-uniform distribution of H”, and how these affect the structural, optical and photoelectric properties of µc-Si1−xGex:H thin films have been explored. The results show that the good film quality of µc-Si1−xGex:H is associated with the low crystalline volume fraction and microstructure factor. The band gap of µc-Si1−xGex:H is determined by the proportion of the Ge-related crystalline networks. In addition, it is suggested that the deterioration of the photosensitivity of µc-Si1−xGex:H is mainly due to the increase of the Ge clusters with higher micro-void and defect density. Furthermore, by using µc-Si1−xGex:H bottom sub-cells, the comparable efficiency can be realized under the thin thickness condition. An efficiency of 11.35% in an a-Si:H/a-Si0.6Ge0.4:H/µc-Si0.5Ge0.5:H triple junction structure with total cell thickness as thin as 1200nm was obtained. It is believed that the µc-Si1−xGex:H thin films can be a better candidate for effective infrared absorber by further improving its microstructure uniformity.

Isothermal crystallization and effect of soak time on phase evolution, microstructure and ionic conductivity of Li2O–Al2O3–TiO2–P2O5 glass–ceramic

Glass–ceramics derived from Li2O–Al2O3–TiO2–P2O5 vitreous system were obtained by isothermal heat treatment at 700°C, for different soak times ranging from 0 to 60h. Phase analysis revealed mixture of amorphous and crystalline phases for short soak times (<1h). By 1h of soak time, crystallization was complete and phases were ascribed to dominant Li1+xAlxTi2−x(PO4)3 (LATP) along with secondary AlPO4 and TiO2, previously reported. Microstructural evolution with soak time was imaged using high resolution scanning electron microscope (SEM). Crystalline volume fraction in glass–ceramics was estimated from image analysis and it followed Kolmogorov–Johnson–Mehl–Avrami (KJMA) equation. Conductivity of glass–ceramics was derived using impedance spectroscopy data for all soak times and correlated to the crystalline volume content. After attaining a critical volume of crystalline phase/s, conductivity increased significantly and was observed to follow the scaling equation σdc~(V−Vc)β, where σdc is dc conductivity, V is crystalline volume content, Vc is threshold value of crystalline volume content above which sudden increase in conductivity was observed and β is scaling exponent. Vc≈30% was in accordance with percolation scaling law and is attributed to formation of 3D conducting channel network in the glass–ceramics microstructure.

Influences of hydrogen dilution on the growth of Si-based core–shell nanowires by HWCVD, and their structure and optical properties

Si-based core–shell nanowires were grown on Ni-coated crystal silicon substrates using a hot-wire chemical vapor deposition technique. The NiSi nanoparticles acted as catalysts that facilitated the growth of the core–shell nanowires without any hydrogen dilution as well as that ranging from 20 to 99 %. These nanowires were structured by single-crystalline NiSi cores and amorphous shells with consisting of nanocrystallites embedded within an amorphous matrix. Raman results reveal crystallization of amorphous Si to crystalline Si up to the crystalline volume fraction of 92.3 % for the nanowires grown with hydrogen dilution. An increase in hydrogen dilution enhanced the decomposition rate and the gas-phase reactions for SiC shell formation, while further increases up to 99 % suppressed the growth of the nanowires. Moreover, a phased transition from Si to SiC occurred with increases in hydrogen dilution above 20 %. The nanowires demonstrated superior optical absorption in the visible region, revealing their significant light-trapping ability. This paper discusses the influences of hydrogen dilution on the structure and optical properties of these core–shell nanowires.

Thermal and enzymatic degradation induced ultrastructure changes in canna starch: Further insights into short-range and long-range structural orders

Slurries of canna starch treated with or without α-amylase were heated at 60 °C to investigate the mechanism of thermal and enzymatic degradation and the effects of these processes on the ultrastructure of starch residues. For this purpose, solid-state 13C CP/MAS NMR, X-ray diffraction (XRD), and small angle X-ray scattering (SAXS) were used to estimate the short- and long-range orders within the structure. Crystal stabilization was observed in both samples of thermally degraded canna starch (TDCS) and enzymatically degraded canna starch (EDCS), and the critical time for the formation of double helical crystals was 3 h for thermal degradation and 5 h for enzymatic degradation. With longer times, imperfect sub-crystal started prevailed. The results showed that when degradation occurs, the crystal lamellae compact, as indicated by a higher crystal density in the structure of EDCS. Moreover, the relationship between crystalline weight and volume fraction as well as short-range and long-range orders were also investigated and found correlate well with each other.

An amorphous-to-crystalline phase transition within thin silicon films grown by ultra-high-vacuum evaporation and its impact on the optical response

A number of thin silicon films are deposited on crystalline silicon, native oxidized crystalline silicon, and optical quality fused quartz substrates through the use of ultra-high-vacuum evaporation at growth temperatures ranging from 98 to 572 °C. An analysis of their grazing incidence X-ray diffraction and Raman spectra indicates that a phase transition, from amorphous-to-crystalline, occurs as the growth temperature is increased. Through a peak decomposition process, applied to the Raman spectroscopy results, the crystalline volume fractions associated with these samples are plotted as a function of the growth temperature for the different substrates considered. It is noted that the samples grown on the crystalline silicon substrates have the lowest crystallanity onset temperature, whereas those grown on the optical quality fused quartz substrates have the highest crystallanity onset temperature; the samples grown on the native oxidized crystalline silicon substrates have a crystallanity onset temperature between these two limits. These resultant dependencies on the growth temperature provide a quantitative means of characterizing the amorphous-to-crystalline phase transition within these thin silicon films. It is noted that the thin silicon film grown on an optical quality fused quartz substrate at 572 °C, possessing an 83% crystalline volume fraction, exhibits an optical absorption spectrum which is quite distinct from that associated with the other thin silicon films. We suggest that this is due to the onset of sufficient long-range order in the film for wave-vector conservation to apply, at least partially. Finally, we use a semi-classical optical absorption analysis to study how this phase transition, from amorphous-to-crystalline, impacts the spectral dependence of the optical absorption coefficient.

Structural and optoelectronic characteristics of nanocrystalline silicon oxide film as absorber layer for thin film solar cells

The mixed phase nanocrystalline silicon oxide (nc-SiOx:H) thin films have been prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) system from SiH4, H2 and CO2 mixture. The effect of oxygen incorporation on the structural and opto-electrical properties of nc-Si:H films was investigated. As the CO2 flow rate increased, the crystalline volume fraction in the films decreased, while the optical band gap increased slowly. During the phase transition, both oxygen and hydrogen content increased drastically with the increasing CO2 flow rate, while the Urbatch energy and microstructure factor showed obvious reduction, which indicated an enhancement of the medium range order of the films and good passivation of the inner voids. Device quality nc-SiOx:H film was fabricated with low microstructure factor of 0.32 and high crystalline volume fraction around 50%, along with wide optical band gap of ∼1.75 eV, low dark-conductivity σd ∼7.6 × 10−6 S/cm and high photosensitivity of about 2 × 102. On flat substrate a solar cell was prepared with high Voc of 0.62 V and Jsc of 14.57 mA/cm2. These results revealed the potential of nc-SiOx:H film as an absorber layer for thin film solar cells.

AC magnetic susceptibility and influence of heat treatment on obtaining the nanocrystalline structure for the amorphous alloy of Fe37Co35Nb6B11Si10Cu1 composition

This work presents a study of AC magnetic susceptibility and the influence of heat treatment on obtaining the nanocrystalline structure for the amorphous alloy of Fe37Co35Nb6B11Si10Cu1 composition. AC magnetic susceptibility at different frequencies and sample lengths, using a variable magnetic field was measured. The influence of heat treatment on obtaining the sample nanocrystalline structure was evidenced by means of XRD technique. The crystallite size, the crystalline volume fraction and the distance between grains for each heat treatment temperature were calculated using the XRD peaks refinement software GSAS. Samples were obtained in the amorphous state by melt spinning technique and all measurements by AC magnetic susceptibility and XRD were performed at room temperature.

Two-phase quasi-equilibrium in β-type Ti-based bulk metallic glass composites.

The microstructural evolution of cast Ti/Zr-based bulk metallic glass composites (BMGCs) containing β-Ti still remains ambiguous. This is why to date the strategies and alloys suitable for producing such BMGCs with precisely controllable volume fractions and crystallite sizes are still rather limited. In this work, a Ti-based BMGC containing β-Ti was developed in the Ti-Zr-Cu-Co-Be system. The glassy matrix of this BMGC possesses an exceptional glass-forming ability and as a consequence, the volume fractions as well as the composition of the β-Ti dendrites remain constant over a wide range of cooling rates. This finding can be explained in terms of a two-phase quasi-equilibrium between the supercooled liquid and β-Ti, which the system attains on cooling. The two-phase quasi-equilibrium allows predicting the crystalline and glassy volume fractions by means of the lever rule and we succeeded in reproducing these values by slight variations in the alloy composition at a fixed cooling rate. The two-phase quasi-equilibrium could be of critical importance for understanding and designing the microstructures of BMGCs containing the β-phase. Its implications on the nucleation and growth of the crystalline phase are elaborated.

Nucleation of microcrystalline silicon: on the effect of the substrate surface nature and nano-imprint topography

The nucleation of microcrystalline silicon thin-films has been investigated for various substrate natures and topographies. An earlier nucleation onset on aluminium-doped zinc oxide compared to glass substrates has been revealed, associated with a microstructure enhancement and reduced surface energy. Both aspects resulted in a larger crystallite density, following classical nucleation theory. Additionally, the nucleation onset was (plasma deposition) condition-dependent. Therefore, surface chemistry and its interplay with the plasma have been proposed as key factors affecting nucleation and growth. As such, preliminary proof of the substrate nature’s role in microcrystalline silicon growth has been provided. Subsequently, the impact of nano-imprint lithography prepared surfaces on the initial microcrystalline silicon growth has been explored. Strong topographies, with a 5-fold surface area enhancement, led to a reduction in crystalline volume fraction of ~20%. However, no correlation between topography and microstructure has been found. Instead, the suppressed crystallization has been partially ascribed to a reduced growth flux, limited surface diffusion and increased incubation layer thickness, originating from the surface area enhancement when transiting from flat to nanostructured surfaces. Furthermore, fundamental plasma parameters have been reviewed in relation with surface topography. Strong topographies are not expected to affect the ion-to-growth flux ratio. However, the reduced ion flux (due to increasing surface area) further limited the already weak ion energy transfer to surface processes. Additionally, the atomic hydrogen flux, i.e. the driving force for microcrystalline growth, has been found to decrease by a factor of 10 when transiting from flat to nanostructured topography. This resulted in an almost 6-fold reduction of the hydrogen-to-growth flux ratio, a much stronger effect than the ion-to-growth flux ratio. Since previous studies regarding crystalline growth stated the necessity for enhanced ion- and atomic hydrogen-to-growth flux ratios, reduction of the latter is suggested to be the main cause of suppressed crystallization kinetics.

Femtosecond Laser Crystallization of Boron-doped Amorphous Hydrogenated Silicon Films

Crystallization of amorphous hydrogenated silicon films with femtosecond laser pulses is one of the promising ways to produce nanocrystalline silicon for photovoltaics. The structure of laser treated films is the most important factor determining materials' electric and photoelectric properties. In this work we investigated the effect of femtosecond laser irradiation of boron doped amorphous hydrogenated silicon films with different fluences on crystalline volume fraction and electrical properties of this material. A sharp increase of conductivity and essential decrease of activation energy of conductivity temperature dependences accompany the crystallization process. The results obtained are explained by increase of boron doping efficiency in crystalline phase of modified silicon film.

Nanoindentation studies of Zr50Cu50metallic glass thin film nanocomposites via molecular dynamics simulations

We carry out molecular dynamics (MD) simulations of nanoindentation on Zr50 Cu50 metallic glass thin films (MGTF) containing reinforced nanocrystallites to investigate the shape, size and volume fraction effects on the load-displacement behaviour. We chose spherical (3.2 nm–6.4 nm diameters) and cylindrical (2 nm diameter × 10 nm height) shape nanocrystallites and their volume fraction have been varied in the range of 14%–50%. Nanoindentation tests are conducted at strain rates of 2.5 × 109 s-1 and 2.5 × 1010 s-1 and temperature of 300 K. For comparison of the indentation behaviour; nanoindentation is also carried out on MGTF. It is found that MGTF reinforced with cylindrically shaped nanocrystallites offer much higher yield load than multi-spherical nanocrystallites. Investigations on the effect of crystallite sizes and volume fraction show that single nanocrystallite reinforced MGTF film exhibits the highest maximum load compared to that reinforced with multi-spherical nanocrystallites. With the increase in crystalline volume fraction of the nanocrystallites the MGTFs yield at lesser load. The strain rate greatly affects the material properties. With the increase in strain rate, the load tends to go up. The atomic displacement vector plots reveal nanocrystallites as obstacles to the movement of atoms of the MGTF.

Developments of c-Si1-xGex:H thin films as near-infrared absorber for thin film silicon solar cells

Hydrogenated microcrystalline silicon germanium (c-Si1-xGex:H) thin films have been developed as alternative bottom sub-cell absorbers for multi-junction thin film silicon solar cells due to their narrower band-gaps and higher absorption coefficients than conventional hydrogenated microcrystalline silicon (c-Si:H) thin films. However, since the structure complexity was increased a lot by Ge incorporation, the influences of c-Si1-xGex:H film properties on Ge composition have not been understood yet. In this work, c-Si1-xGex:H thin films with various Ge content and similar crystalline volume fraction are fabricated by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD). The evolutions of c-Si1-xGex:H material properties by Ge incorporation are characterized by X-ray fluorescence spectrometry, Raman spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, absorption coefficient spectrum, and conductivity measurement. The results show that the properties of c-Si1-xGex:H thin films are strongly determined by Ge content. With the increase of Ge content, the absorption coefficient, (111) grain size, microstructure factor, and dark conductivity of c-Si1-xGex:H thin films increase, while the H content, (220) grain size, and photosensitivity of c-Si1-xGex:H thin film decrease. Then, c-Si1-xGex:H is used as the intrinsic layer in the single junction solar cells. The performances of c-Si1-xGex:H solar cells with different Ge content and two types of transparent conductive oxide (SnO2 and ZnO) substrates are systematically studied. The results indicate that although c-Si1-xGex:H thin films become more defective and less compact with Ge incorporation, c-Si1-xGex:H solar cells exhibit a significant improvement in near-infrared response, especially under the circumstances of thin cell thickness and inefficient light trapping structure. Meanwhile, by using ZnO substrates, initial efficiencies of 7.15% (Jsc=22.6 mA/cm2, Voc=0.494 V, FF=64.0%) and 7.01% (Jsc=23.3 mA/cm2, Voc=0.482 V, FF=62.4%) are achieved by c-Si0.9Ge0.1:H solar cell and c-Si0.73Ge0.27:H solar cell, respectively. Furthermore, the c-Si0.73Ge0.27:H solar cell is used as the bottom sub-cell of the double-junction solar cell, and a Jsc.bottom of 12.30 mA/cm2 can be obtained with the bottom sub-cell thickness as thin as 800 nm, which is even higher than that of c-Si:H bottom sub-cell with 1700 nm thickness. Finally, an initial efficiency of 10.28% is achieved in an a-Si:H/c-Si0.73Ge0.27:H double junction cell structure. It is demonstrated that by using the c-Si1-xGex:H solar cell as the bottom sub-cell in multi-junction thin film silicon solar cells, a higher tandem cell performance can be achieved with a thin thickness, which has a great potential for cost-effective photovoltaics.

Study of deposition temperature on high crystallinity nanocrystalline silicon thin films with in-situ hydrogen plasma-passivated grains

This paper studies the effect of deposition temperature on the growth of nanocrystalline silicon (nc-Si) films deposited by 13.56MHz plasma enhanced chemical vapor deposition (PECVD) with in-situ hydrogen (H) passivation. A high crystalline volume fraction (XC) of 80% was found in the ~100nm nc-Si film deposited at 260°C with 99% H2 diluted SiH4 at intermediate RF power between the power-limited and precursor-limited regimes. Based on these optimized deposition conditions, 300–400nm nc-Si films deposited at 75–260°C also showed a high XC of 82–85%, an intrinsic-like dark-conductivity (σdark) of ~10−6S/cm, and even a low mean oxygen content (CO) of 1017–1018at./cm3. Although material properties were similar, deposition temperature appeared to change the qualitative structure of the nanocrystalline grains. The preferred grain orientation changed from 〈111〉 to 〈220〉 as the deposition temperature was increased from 75 to 260°C due to enhanced surface diffusion of deposition precursors. This reflected in more compact and lateral columnar growth of nc-Si films with increasing deposition temperature. We successfully demonstrated high field-effect hole and electron mobilities of 33.8 and 225cm2/Vs, respectively, in top-gate thin-film transistors (TFTs) employing the ~100nm nc-Si channel layer deposited at 260°C.

Nanocrystalline silicon embedded in silicon suboxide synthesized in high-density inductively coupled plasma

A two-phase material system of nanocrystalline silicon (nc-Si) embedded in a dielectric matrix of silicon suboxide (SiOx) is fundamentally and technologically significant for the photonic and photovoltaic device such as light emission diode and solar cells. nc-Si in amorphous SiOx has been synthesized by means of the low-frequency (460 kHz) inductively coupled plasma (LFICP) of SiH4 + CO2 + H2 without the common route of high hydrogen dilution. The chemical composition, microstructures and optical properties of the complex material system are tuned by the reactive gas flow rate ratio of CO2/SiH4. nc-Si embedded in amorphous SiOx due to the phase separation are observed by means of SEM and TEM characterization tools. The crystalline volume fraction in nc-SiOx:H is determined by the density of the embedded nc-Si particles and the occurrence of the a-SiOx encapsulating shell layer. The bond configuration analysis shows the concurrent oxygenation and dehydrogenation process with the incorporation of oxygen. The underlying mechanism in forming the two-phase complex material system and the phase evolution with the reactive gas flow rate ratio are discussed in terms of the unique features of the utilized high-density LFICP.