In-Depth Characterization of Secondary Phases in Cu2ZnSnS4 Film and Its Application to Solar Cells

Secondary phases are common in Cu2ZnSnS4 (CZTS) thin films, which can be fatal to the performance of solar cell devices fabricated from this material. They are difficult to detect by X-Ray diffraction (XRD) because of the weak peak in spectra compared with the CZTS layer. Herein, it was found that in-depth elemental distribution by a secondary ion mass spectroscopy method illustrated uniform film composition in the bulk with slight fluctuation between different grains. X-ray photoelectron spectroscopy (XPS) measurement was conducted after sputtering the layer with different depths. An Auger electron spectrum with Auger parameter were used to check the chemical states of elements and examine the distribution of secondary phases in the CZTS films. Secondary phases of CuS, ZnS and SnS were detected at the surface of the CZTS film within a 50-nm thickness while no secondary phases were discovered in the bulk. The solar cell fabricated with the as-grown CZTS films showed a conversion efficiency of 2.1% (Voc: 514.3 mV, Jsc: 10.4 mA/cm2, FF: 39.3%) with an area of 0.2 cm2 under a 100 mW/cm2 illumination. After a 50-nm sputtering on the CZTS film, the conversion efficiency of the solar cell was improved to 6.2% (Voc: 634.0 mV, Jsc: 17.3 mA/cm2, FF: 56.9%).

Download Full-text

Preparation of ZrO2 in SiC coating via hydrothermal method and sintering process onto carbon/carbon composite

Materials Express ◽

10.1166/mex.2021.1883 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1997-2003

Author(s):

Zu-Li Mao ◽

Li Yang ◽

Jie Wu

Keyword(s):

Hydrothermal Method ◽

Photoelectron Spectroscopy ◽

Carbon Composite ◽

Elemental Distribution ◽

Sintering Process ◽

X Ray Diffraction ◽

Carbon Phase ◽

X Ray ◽

Sem Image ◽

Chemical States

To reduce the defects in SiC coating, a SiC/ZrO2 composite is prepared and coated onto carbon/carbon composite via hydrothermal method and sintering process. The microstructure, surface morphology, chemical states, and elemental distribution of SiC/ZrO2 coating are analysed with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). In addition, we analyze the tribological behavior of the SiC and SiC/SiC/ZrO2 coatings and the related microstructure. The results show that SiC/ZrO2 coating is composed of SiC phase, ZrO2 phase, carbon phase, and SiO2 phase. EDS results show that Si, C, O, and Zr elements are present in the SiC/ZrO2 coating. Moreover, XPS results show the presence of SiC, ZrO2, and SiO2. According to the SEM image, the coating is dense except for some observable cracks. Notably, specimens with the SiC/ZrO2 coating have smaller, more stable friction coefficients and less weight loss than specimens with the SiC-only coating. The formation of ZrO2 strengthens the SiC coating, while the SiO2 formed in the coating acts as a lubricant and reduces the friction coefficient of the coating.

Download Full-text

Room-Temperature Formation of Hard BCx Films by Low Power Magnetron Sputtering

Applied Sciences ◽

10.3390/app11219896 ◽

2021 ◽

Vol 11 (21) ◽

pp. 9896

Author(s):

Veronica Sulyaeva ◽

Maxim Khomyakov ◽

Marina Kosinova

Keyword(s):

Magnetron Sputtering ◽

Photoelectron Spectroscopy ◽

Room Temperature ◽

X Ray Diffraction ◽

Film Properties ◽

X Ray ◽

Sputtering Power ◽

Chemical States ◽

Rf Signal ◽

Dual Target

Boron carbide is one of the most important non-metallic materials. Amorphous BCx films were synthesized at room temperature by single- and dual-target magnetron sputtering processes. A B4C target and C target were operated using an RF signal and a DC signal, respectively. The effect of using single- and dual-target deposition and process parameters on the chemical bonding and composition of the films as well as their functional properties were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray energy dispersive analysis, X-ray diffraction, ellipsometry, and spectrophotometry. It was found that the film properties depend on the sputtering power and the used targets. EDX data show that the composition of the samples varied from B2C to practically BC2 in the case of using an additional C target. According to the XPS data, it corresponds to the different chemical states of the boron atom. A nanoindentation study showed that the film with a composition close to B2C deposited with the highest B4C target power reached a hardness of 25 GPa and Young’s modulus of 230 GPa. The optical properties of the films also depend on the composition, so the band gap (Eg) of the BCx film varied in the range of 2.1–2.8 eV, while the Eg of the carbon-rich films decreased to 1.1 eV.

Download Full-text

Li-DOPING EFFECT ON THE CATHODOLUMINESCENT PROPERTIES OF Y2O3:Eu3+ PHOSPHORS

Surface Review and Letters ◽

10.1142/s0218625x07009797 ◽

2007 ◽

Vol 14 (04) ◽

pp. 535-538 ◽

Cited By ~ 15

Author(s):

J. S. BAE ◽

J. H. YOON ◽

S. K. PARK ◽

J. P. KIM ◽

E. D. JEONG ◽

...

Keyword(s):

Surface Morphology ◽

Photoelectron Spectroscopy ◽

Luminescent Properties ◽

X Ray Diffraction ◽

X Ray ◽

Li Doping ◽

Enhanced Photoluminescence ◽

Chemical States ◽

Structural Surface ◽

The Relationship

Influence of lithium doping on the crystallization, the surface morphology, the chemical states and the luminescent properties of Y 2 O 3: Eu 3+ phosphors was investigated. The structural, surface morphology characteristics and chemical states of the phosphors were analyzed by using X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS), respectively. The crystallinity, the surface morphology, and the cathodoluminescence (CL) of phosphors highly depended on the Li doping. The relationship between the crystalline and morphological structures and the luminescent properties was studied, and Li + doping affected not only the crystallinity but also the luminescent brightness of Y 2 O 3: Eu 3+ phosphors. In particular, the incorporation of the Li + ion into the Y 2 O 3 lattice could induce remarkable increase in the CL intensity. The enhanced photoluminescence brightness with Li doping may result both from the improved crystallinity leading to higher oscillating strengths for the optical transitions, and the increased surface area due to the larger particle sizes. The strongest emission intensity was observed with Li doped Y 2 O 3: Eu 3+ ceramics whose brightness was increased by a factor of 1.8 in comparison with that of Y 2 O 3: Eu 3+ ceramics.

Download Full-text

The Evaluation of SrBi2Ta2O9 Films for Ferroelectric Memories

MRS Proceedings ◽

10.1557/proc-433-109 ◽

1996 ◽

Vol 433 ◽

Cited By ~ 28

Author(s):

C.D. Gutleben

Keyword(s):

Photoelectron Spectroscopy ◽

Layer Structure ◽

Secondary Phases ◽

X Ray Diffraction ◽

X Ray ◽

Annealing Conditions ◽

Complete Knowledge ◽

Scientific Goal ◽

Ferroelectric Memories ◽

Insight Into

AbstractFor use in ferroelectric memories, the layer structure ferroelectric SrBi2Ta2O9 (SBT) appears to have some stability-related advantages over the more commonly known PZT class of ferroelectrics. Currently we are evaluating the feasibility of integrating this material into a state of the art CMOS memory process. Our primary scientific goal is to identify the intrinsic limitations of SBT which may restrict the engineering applications of films grown by even perfectly optimized processes. To this end we have utilized a wide variety of microanalysis probes to examine polycrystaline SBT films grown under various conditions by both MOD and Flash MOCVD. We have found that X-ray diffraction methods must be supplemented by high resolution X-ray photoelectron spectroscopy (XPS) in order to fully analyze the secondary phases which are commonly incorporated in SBT films. The more complete knowledge of film microstructure that this provides has enabled us to relate phase structure to growth and annealing conditions. XPS has also given us some insight into the initial stages of the growth chemistry of SBT on various Pt surfaces.

Download Full-text

Enhancement of Solar Cell Performance of Electrodeposited Ti/n-Cu2O/p-Cu2O/Au Homojunction Solar Cells by Interface and Surface Modification

Crystals ◽

10.3390/cryst10070609 ◽

2020 ◽

Vol 10 (7) ◽

pp. 609 ◽

Cited By ~ 1

Author(s):

Charith Jayathilaka ◽

Loku Singgappulige Rosantha Kumara ◽

Koji Ohara ◽

Chulho Song ◽

Shinji Kohara ◽

...

Keyword(s):

Solar Cell ◽

Current Density ◽

Photoelectron Spectroscopy ◽

Open Circuit Voltage ◽

Short Circuit ◽

High Energy ◽

Open Circuit ◽

X Ray Diffraction ◽

Solar Cell Performance ◽

X Ray

Cuprous oxide (Cu2O) homojunction thin films on Ti substrates were fabricated by an electrochemical deposition in which a p-Cu2O layer was deposited on an n-Cu2O layer by carefully controlled bath conditions. It was found that the open-circuit voltage of the homojunction solar cell was significantly influenced by the pH of the lactate bath. The variation of the pH was used to achieve the best possible crystal orientation for homojunctions. The crystallinity and morphology of the products were characterized by X-ray diffraction (XRD), high-energy x-ray diffraction (HEXRD), and scanning electron microscopy (SEM). The current density voltage (J-V) analysis showed that the sulfur treatment and annealing enhanced the photocurrent by ten-fold compared to the untreated and unannealed homojunction solar cell. X-ray photoelectron spectroscopy (XPS) studies confirmed that the sulfur treatment eliminated the surface CuO and formed a thin layer of CuS, which was very useful to make the front Ohmic contact. Transient measurements confirmed that the p-type Cu2O layer, which was subjected to sulfur treatment, significantly reduced the recombination, thus enhancing the efficiency of the solar cell. The best sulfur treated annealed Ti/n-Cu2O/p-Cu2O/Au solar cell produced an energy conversion efficiency of 2.64% with an open-circuit voltage of 490 mV and a short circuit current density of 12.8 mA cm−2 under AM 1.5 illumination.

Download Full-text

Identification of Secondary Phases in Cu2ZnSnS4 Layers by In-depth Resolved X-ray Photoelectron Spectroscopy Analysis

10.20944/preprints201701.0064.v1 ◽

2017 ◽

Author(s):

Xianfeng Zhang ◽

M. Kobayashi

Keyword(s):

Photoelectron Spectroscopy ◽

Film Surface ◽

Secondary Phase ◽

Czts Film ◽

Xps Analysis ◽

Secondary Phases ◽

Phase Layer ◽

X Ray ◽

Depth Direction ◽

Nanoparticle Ink

A Cu2ZnSnS4 (CZTS) film with a thickness of approximately 1.5 μm was fabricated on a Mo-coated glass substrate by annealing a CZTS precursor fabricated from nanoparticle ink. The chemical states of the elements in the CZTS thin film in the depth direction were studied to identify the presence of secondary phases, which are detrimental to the performance of solar cells containing CZTS. X-ray diffraction was unable to detect any secondary phases in CZTS because of their small relative amount. Instead, X-ray photoelectron spectroscopy (XPS), which is highly sensitive to chemical state, was conducted at different depths in the CZTS film to further check the presence of secondary phases. XPS analysis revealed peaks shift consistent with the presence of secondary phases. For the CZTS film annealed in a S atmosphere at 575 °C for 3 h, the film surface consisted of a secondary-phase layer composed of CuS, ZnS, and SnSx (x=1 or 2) originating from the decomposition of CZTS. At depths below 80 nm, the film was pure CZTS. Formation of MoS2 at the CZTS–Mo interface was confirmed by XPS analysis of Mo and S.

Download Full-text

Surface Properties of the Ta and Ag Dual-Ion-Implanted Ti6Al4V Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.738.78 ◽

2013 ◽

Vol 738 ◽

pp. 78-82

Author(s):

Chong Yan Leng ◽

Rong Zhou ◽

Xu Zhang

Keyword(s):

Phase Composition ◽

Diffraction Analysis ◽

Photoelectron Spectroscopy ◽

Ti6al4v Alloy ◽

X Ray Diffraction ◽

Spectroscopy Analysis ◽

X Ray ◽

Glancing Angle ◽

Chemical States ◽

Ion Implanted

First, Ti6Al4V alloy samples were modified by tantalum ion implantation at a dose of 1.5×1017ions/cm2, and then silver ion at a dose of 1×1017ions/cm2. Glancing angle X-ray diffraction analysis was used to characterize the phase composition of un-implanted Ti6Al4V alloy and Ta+Ag dual-ion-implanted Ti6Al4V alloy samples. X-ray photoelectron spectroscopy analysis was used to investigate the chemical states of the elements on the Ta+Ag dual-ion-implanted Ti6Al4V alloy sample’s surface. The results show that small amounts of Ta and Ag were present in their elementary forms, along with TiO2, Ta2O5, and TaOx.

Download Full-text

Mixed valence Sn doped (CH3NH3)3Bi2Br9 produced by mechanochemical synthesis

10.26434/chemrxiv-2021-mr4lb ◽

2021 ◽

Author(s):

Xiaohan Jia ◽

Yuhan Liu ◽

Robin Perry ◽

Ivan Parkin ◽

Robert Palgrave

Keyword(s):

Photoelectron Spectroscopy ◽

Room Temperature ◽

Near Infrared ◽

Mixed Valence ◽

Mechanochemical Reaction ◽

Luminescent Materials ◽

Secondary Phases ◽

X Ray Diffraction ◽

X Ray ◽

Solar Absorbers

Bismuth halides with formula A3Bi2X9, where A is an inorganic or organic cation, show desirable properties as solar absorbers and luminescent materials. Control of structural and electronic dimensionality of these compounds is important to yield materials with good light absorption and charge transport. Here we report mechanochemical reaction of (CH3NH3)3Bi2Br9 with SnBr2 at room temperature in air, yielding a material with strong absorption across the visible and near-infrared (NIR) region. We attribute this to mixed valence doping of Sn(II) and Sn(IV) on the Bi site. X-ray diffraction shows no secondary phases, even after heating at 200oC to improve crystallinity. X-ray photoelectron spectroscopy suggests the presence of Sn(II) and Sn(IV) states. A similar approach to dope Sn into the iodide analogue (CH3NH3)3Bi2I9 was unsuccessful.

Download Full-text

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

MRS Proceedings ◽

10.1557/proc-780-y5.5 ◽

2003 ◽

Vol 780 ◽

Author(s):

C. Essary ◽

V. Craciun ◽

J. M. Howard ◽

R. K. Singh

Keyword(s):

Uv Radiation ◽

Photoelectron Spectroscopy ◽

Grazing Angle ◽

X Ray Diffraction ◽

Metal Thin Films ◽

X Ray ◽

Force Microscopy ◽

Si Substrates ◽

Atomic Force ◽

Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Download Full-text

α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽

10.3390/polym13040581 ◽

2021 ◽

Vol 13 (4) ◽

pp. 581

Author(s):

Gajanan S. Ghodake ◽

Surendra K. Shinde ◽

Ganesh D. Saratale ◽

Rijuta G. Saratale ◽

Min Kim ◽

...

Keyword(s):

Enzyme Immobilization ◽

Photoelectron Spectroscopy ◽

Cellulose Fibers ◽

Relative Activity ◽

Significant Activity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Laccase Immobilization ◽

Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

Download Full-text