scholarly journals Biochar as a low-cost, eco-friendly, and electrically conductive material for terahertz applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Woongkyu Park ◽  
Hyuntae Kim ◽  
Hajung Park ◽  
Soobong Choi ◽  
Sung Ju Hong ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Low Cost ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
High Annealing ◽  
Structural And Electrical Properties ◽  
Terahertz Frequencies ◽  
Terahertz Conductivity

AbstractWe investigate conducting characteristics of biochar derived from the pyrolysis of a paper at terahertz frequencies. Paper is annealed under temperatures ranging from 600 to 1000 °C to modify structural and electrical properties. We experimentally observe that the terahertz conductivity increases above 102 S/m as the annealing temperature increases up to 800 °C. From structural characterization using energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, we confirm that more graphitic biochars are produced in high annealing temperature, in agreement with the improvement of terahertz conductivity. Our results show that biochar can be a highly promising candidate to be used in paper-based devices operating at terahertz frequencies.

scholarly journals Effects of Thermal Annealing on the Properties of Zirconium-Doped MgxZn1−XO Films Obtained through Radio-Frequency Magnetron Sputtering

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 373
Author(s):  
Wen-Yen Lin ◽  
Feng-Tsun Chien ◽  
Hsien-Chin Chiu ◽  
Jinn-Kong Sheu ◽  
Kuang-Po Hsueh
Keyword(s):  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Radio Frequency Magnetron ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Free Electrons ◽  
X Ray ◽  
Mg Content

Zirconium-doped MgxZn1−xO (Zr-doped MZO) mixed-oxide films were investigated, and the temperature sensitivity of their electric and optical properties was characterized. Zr-doped MZO films were deposited through radio-frequency magnetron sputtering using a 4-inch ZnO/MgO/ZrO2 (75/20/5 wt%) target. Hall measurement, X-ray diffraction (XRD), transmittance, and X-ray photoelectron spectroscopy (XPS) data were obtained. The lowest sheet resistance, highest mobility, and highest concentration were 1.30 × 103 Ω/sq, 4.46 cm2/Vs, and 7.28 × 1019 cm−3, respectively. The XRD spectra of the as-grown and annealed Zr-doped MZO films contained MgxZn1−xO(002) and ZrO2(200) coupled with Mg(OH)2(101) at 34.49°, 34.88°, and 38.017°, respectively. The intensity of the XRD peak near 34.88° decreased with temperature because the films that segregated Zr4+ from ZrO2(200) increased. The absorption edges of the films were at approximately 348 nm under 80% transmittance because of the Mg content. XPS revealed that the amount of Zr4+ increased with the annealing temperature. Zr is a potentially promising double donor, providing up to two extra free electrons per ion when used in place of Zn2+.

scholarly journals Nanosheets of CuCo2O4 As a High-Performance Electrocatalyst in Urea Oxidation

2019 ◽  
Vol 9 (4) ◽  
pp. 793 ◽  
Author(s):  
Camila Zequine ◽  
Fangzhou Wang ◽  
Xianglin Li ◽  
Deepa Guragain ◽  
S.R. Mishra ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Nickel Foam ◽  
Low Cost ◽  
Agricultural Waste ◽  
Bifunctional Catalyst ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electroactive Material

The urea oxidation reaction (UOR) is a possible solution to solve the world’s energy crisis. Fuel cells have been used in the UOR to generate hydrogen with a lower potential compared to water splitting, decreasing the costs of energy production. Urea is abundantly present in agricultural waste and in industrial and human wastewater. Besides generating hydrogen, this reaction provides a pathway to eliminate urea, which is a hazard in the environment and to people’s health. In this study, nanosheets of CuCo2O4 grown on nickel foam were synthesized as an electrocatalyst for urea oxidation to generate hydrogen as a green fuel. The synthesized electrocatalyst was characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electroactivity of CuCo2O4 towards the oxidation of urea in alkaline solution was evaluated using electrochemical measurements. Nanosheets of CuCo2O4 grown on nickel foam required the potential of 1.36 V in 1 M KOH with 0.33 M urea to deliver a current density of 10 mA/cm2. The CuCo2O4 electrode was electrochemically stable for over 15 h of continuous measurements. The high catalytic activities for the hydrogen evolution reaction make the CuCo2O4 electrode a bifunctional catalyst and a promising electroactive material for hydrogen production. The two-electrode electrolyzer demanded a potential of 1.45 V, which was 260 mV less than that for the urea-free counterpart. Our study suggests that the CuCo2O4 electrode can be a promising material as an efficient UOR catalyst for fuel cells to generate hydrogen at a low cost.

An Efficient Simple Hydrothermal Method to Synthesis FeS2 Microspheres and their Optical Property

2016 ◽  
Vol 847 ◽  
pp. 72-77
Author(s):  
Yu Xuan Liang ◽  
Peng Peng Bai ◽  
Shu Qi Zheng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Wave Length ◽  
Functional Materials ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
Synthetic Sample ◽  
X Ray ◽  
New Type ◽  
Good Uniformity

Pyrite (FeS2) is an important semiconductor material which shows various excellent optical and electrical properties and extensive applied prospect as a new-type, photoelectrical functional materials. In this study, a low cost and efficient simple hydrothermal two-step synthetic method was given to obtain FeS2 microspheres with 2-3 μm in diameter. The obtained products were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet and visible spectrophotometer (UV-Vis). XRD showed that the synthetic sample consisted of two crystal structures of FeS2, pyrite and marcasite. SEM observation indicated that FeS2 microspheres were well crystallized and had good uniformity. UV-Vis spectrum had a strong optical absorption in the region of 200-400 nm wave length. The reaction temperature had an impact on the size of FeS2 microspheres. A possible mechanism for the size of the FeS2 microspheres generated at high temperature is smaller than that at low temperature is discussed.

Aluminium Induced Crystallization of Amorphous Silicon via Solution Derived Catalyst

2013 ◽  
Vol 481 ◽  
pp. 3-6
Author(s):  
Ian Yi Yu Bu
Keyword(s):  
Annealing Temperature ◽  
Preparation Method ◽  
Low Cost ◽  
Vacuum Solution ◽  
Solution Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Induced Crystallization ◽  
Probe Measurements

In this paper, aluminum induced crystallization (AIC) was studied by examining the effect of using solution derived AlCl3 catalyst. Such catalyst preparation method offers possibility of low-cost, non-vacuum solution process and allows examination of the role of alumina on the AIC process. The deposited AIC films were examined by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Raman spectroscopy, X-ray diffraction (XRD) and four probe measurements. It was found that AIC process is highly dependent on annealing temperature and can occur at annealing temperatures above 500°C through Al2O3 formation. Based on the presented data, a possible growth model is proposed to clarify AIC mechanism.

Defect-Related Photoluminescence from SiO2 Thin Films by Si-Ge Ions Doped

2011 ◽  
Vol 328-330 ◽  
pp. 1153-1156 ◽  
Author(s):  
Kun Zhong ◽  
Yan Dong Xia ◽  
Ju Hong Miao ◽  
Jiang Fu
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Annealing Treatment ◽  
X Ray Diffraction ◽  
X Ray

Si and Ge ions are implanted into SiO2thin films, subsequently the annealing treatment are carried out. The samples exhibit photoluminescence (PL) peaks at 400, 470, 550 and 780 nm. With the annealing temperature increasing, the intensity of 400-470 nm PL band increases remarkably. After oxidation annealing treatment, the intensity of 400-470 nm PL band decreases, and that of 550 nm and 780 nm PL peaks rises. Combing with the results of X-ray photoelectron spectroscopy(XPS), X-ray diffraction (XRD) and PL measurement, we propose that the PL peaks at 400 nm, 470 nm, 550 nm and 780 nm originate from ≡Ge−Si≡ center, ≡Si−Si≡ center, SPR center and GeO center, respectively.

Low Cost Integrated Sensors Utilizing Patterned Nano-Structured Titania Arrays Fabricated Using a Simple Process

2004 ◽  
Vol 828 ◽  
Author(s):  
Zuruzi Abu Samah ◽  
Andrei Kolmakov ◽  
Martin Moskovits ◽  
Noel C. MacDonald
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide ◽  
X Ray ◽  
Sensing Systems ◽  
Potential Applications ◽  
Nano Wires ◽  
Low Temperature Process

ABSTRACTUsing a novel low-temperature process, we demonstrate the facile integration of crack-free nanostructured titania (NST) as sensing elements in microsystems. Unlike conventional sol-gel methods, NST layers of interconnected nano-walls and nano-wires were formed by reacting Ti surfaces with aqueous hydrogen peroxide solution. Cracks were observed in NST layers formed on blanket Ti films but absent on arrays of patterned Ti pads below a threshold dimension. Analyses using TEM, high resolution SEM, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that NST consists of anatase TiO2 nano-crystals. NST pads were found able to detect oxygen gas of a few ppm. NST pad arrays were integrated on rigid and flexible substrates with potential applications in low cost and wearable sensing systems.

Electrical and Structural Properties of Ruthenium Film Grown by Atomic Layer Deposition Using Liquid-Phase Ru(CO)3(C6H8) Precursor

2007 ◽  
Vol 990 ◽  
Author(s):  
Sung-Hoon Chung ◽  
Vladislav Vasilyev ◽  
Evgeni Gorokhov ◽  
Yong-Won Song ◽  
Hyuk-Kyoo Jang
Keyword(s):  
Liquid Phase ◽  
Atomic Layer Deposition ◽  
Annealing Temperature ◽  
Atomic Layer ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Layer Deposition ◽  
Structural And Electrical Properties

ABSTRACTWe investigated effects of thermal annealing on Ru films deposited on the 8 inch Si substrates using a volatile liquid-phase Ru precursor, tricarbonyl-1,3-cyclohexadienyl ruthenium (Ru(CO)3(C6H8)) by an atomic layer deposition (ALD) technique. Structural and electrical properties of the films were characterized by scanning probe microscopy, X-ray diffractometry, sheet resistance. Grazing incidence X-ray diffraction (GIXRD) patterns show typical Ru hexagonal polycrystalline peaks as annealing temperature was increased. At the highest annealing temperature condition, Ta = 700 °C electrical resistivity become 6 times less than in as-deposited films.

scholarly journals Annealing-Driven Microstructural Evolution and Its Effects on the Surface and Nanomechanical Properties of Cu-Doped NiO Thin Films

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 107 ◽  
Author(s):  
San-Ho Wang ◽  
Sheng-Rui Jian ◽  
Guo-Ju Chen ◽  
Huy-Zu Cheng ◽  
Jenh-Yih Juang
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Film Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanomechanical Properties ◽  
Glass Substrates ◽  
Structural Surface ◽  
Diffraction Peaks

The effects of annealing temperature on the structural, surface morphological and nanomechanical properties of Cu-doped (Cu-10 at %) NiO thin films grown on glass substrates by radio-frequency magnetron sputtering are investigated in this study. The X-ray diffraction (XRD) results indicated that the as-deposited Cu-doped NiO (CNO) thin films predominantly consisted of highly defective (200)-oriented grains, as revealed by the broadened diffraction peaks. Progressively increasing the annealing temperature from 300 to 500 °C appeared to drive the films into a more equiaxed polycrystalline structure with enhanced film crystallinity, as manifested by the increased intensities and narrower peak widths of (111), (200) and even (220) diffraction peaks. The changes in the film microstructure appeared to result in significant effects on the surface energy, in particular the wettability of the films as revealed by the X-ray photoelectron spectroscopy and the contact angle of the water droplets on the film surface. The nanoindentation tests further revealed that both the hardness and Young’s modulus of the CNO thin films increased with the annealing temperature, suggesting that the strain state and/or grain boundaries may have played a prominent role in determining the film’s nanomechanical characterizations.

scholarly journals Sorption of Molybdates and Tungstates on Functionalized Montmorillonites: Structural and Textural Features

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2253 ◽  
Author(s):  
Magdalena Tuchowska ◽  
Barbara Muir ◽  
Mariola Kowalik ◽  
Robert P. Socha ◽  
Tomasz Bajda
Keyword(s):  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Inorganic Compounds ◽  
Ammonium Bromide ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Mineral Sorbent ◽  
Dimethyl Ammonium

Montmorillonite—the most popular mineral of the smectite group—has been recognized as a low-cost, easily available mineral sorbent of heavy metals and other organic and inorganic compounds that pollute water. The aim of this work was to determine the sorption mechanism and to identify the reaction products formed on the surface of montmorillonite and organo-montmorillonite after sorption of molybdates (Mo(VI)) and tungstates (W(VI)). Montmorillonites are often modified to generate a negative charge on the surface. The main objective of the study was to investigate and compare the features of Na-montmorillonite (Na-M), montmorillonite modified with dodecyl trimethyl ammonium bromide (DDTMA-M), and montmorillonite modified with didodecyl dimethyl ammonium bromide (DDDDMA-M) before and after sorption experiments. The material obtained after sorption was studied by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed the presence of a new crystallic phase in the sample that was observed under an SEM as an accumulation of crystals. The FTIR spectra showed bands related to Mo–O and W–O vibration (840 and 940 cm−1, respectively). The obtained results suggest that molybdenum(VI) and tungsten(VI) ions sorb onto the organo-montmorillonite in the form of alkylammonium molybdates and tungstates.

Effect of Annealing Temperature on the Optical and Structural Properties of Ge Doped ZnO Films

2011 ◽  
Vol 304 ◽  
pp. 79-83
Author(s):  
Dong Hua Fan ◽  
Kai Zhen Huang ◽  
Yu Bao Huang
Keyword(s):  
Structural Properties ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Free Exciton ◽  
Ultra Violet ◽  
Zno Films ◽  
Violet Emission ◽  
X Ray ◽  
High Annealing ◽  
Doped Zno

Ge doped ZnO films were synthesized on silicon substrate via RF magnetron co-sputtering methods. The effects of annealing temperature on the optical and structural properties of the Ge doped ZnO films were investigated by means of photoluminescence spectra, X-ray diffraction, and X-ray Photoelectron Spectroscopy. The ultra-violet emission should be related with the free-exciton recombination, and blue and yellow emissions should be attributed to the defect state caused by Ge. The varieties of annealing temperature affect greatly the optical properties. The high annealing temperature leads to the oxidation of Ge and the formation of Zn2GeO4, which could lead to the change of PL spectra.

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