Browsing by Author Nguyen, Viet Tuyen

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  • 4365-97-9282-1-10-20191218.pdf.jpg
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  • Authors: Tran, Thi Ngoc Anh; Tran, Thi Ha; Nguyen, Viet Tuyen; Pham, Nguyen Hai (2019)

  • This paper presents results of preparation of Ag doped ZnO bulk sample by solid state reaction and Ag doped ZnO thin films by sputtering method. Effect of doping concentration (1, 2 and 4%) on the properties of the thin films was investigated. Various methods were utilized to investigate characteristics of the samples: X-ray diffraction, Raman scattering spectroscopy, photoluminescence, energy dispersive X-Ray spectroscopy, scanning electron microscopy, atomic force microscope, absorption spectroscopy and Hall measurement. The results show that Ag diffused into ZnO crystal lattice after heat treatment at 1200oC. As-prepared thin film samples exhibit low resistivity in the order of 10-...

  • Effect of Annealing Temperature on Cu2O Thin Films Prepared by Thermal Oxidation Method.pdf.jpg
  • Article


  • Authors: Tran, Thi Ha; Nguyen, Thi Huyen Trang; Bach, Thanh Cong; Nguyen, Thi Dieu Thu; Nguyen, Thanh Binh; Nguyen, Viet Tuyen; Pham, Nguyen Hai (2020)

  • We report a facile process to fabricate cuprous thin films by thermal oxidation of copper substrates. Structure and phase identification were studied by X-ray diffraction measurement and Raman spectroscopy. Scanning electron microscopy was utilized to study surface morphology of the as-fabricated thin films and optical properties of the samples were investigated by diffused reflectance spectroscopy. The study shows that cuprous thin films could be obtained by controlling annealing temperature in the region of 200-300 oC.

  • 4280-97-8419-1-10-20180924.pdf.jpg
  • Article


  • Authors: Pham, Thi Hong; Nguyen, Viet Tuyen; Tran, Thi Ha (2018)

  • Cu2ZnSnS4 (CZTS) is a p-type semiconductor with high absorption coefficient and direct bandgap from 1 to 1.5 eV, which is ideal for making absorber layer for solar cell. However, it is difficult to get single phase of CZTS due to the competitive formation of binary and ternary secondary phases. In this paper, we prepared CZTS nanoparticles by hydrothermal method and investigate the influence of hydrothermal temperature on the product. Raman scattering, X-ray diffraction, scanning electron microcopy, energy dispersive X-ray spectroscopy and diffusion reflective measurement were applied to characterize the products. The products are high quality nanocrystals of kesterite phase with unif...

  • 21.pdf.jpg
  • Article


  • Authors: Nguyen, Viet Tuyen; Tran, Thi Hai; Nguyen, Thi Hong; Phan, Thi Thanh Hong; Ho, Khac Hieu (2017)

  • The anharmonic correlated Debye model has been developed to investigate the pressure effects on the extended X-ray absorption fine structure (EXAFS) Debye-Waller factors of metals. The recent well-established Grüneisen parameter expressions have been applied to formulate the pressure-dependent analytical expressions of the effective spring constant, correlated Debye frequency and temperature. Combing with the anharmonic correlated Debye model, the expression of EXAFS Debye–Waller factor under pressure can be derived. Numerical calculations, performed for Fe and Cu metals show reasonable agreement with experiments.

  • 98.pdf.jpg
  • Article


  • Authors: Ta, Dinh Canh; Nguyen, Viet Tuyen; Nguyen, Ngoc Long (2009)

  • A simple and rapid process has been developed for preparation of nanometer-sized ZnO powders via microwave irradiation, by which ZnO powders with an average particle size of 10-12 nm and narrow size distribution can be synthesized in a short time. We have synthesized ZnO nanoparticles by precipitation from zinc acetate (Zn(CH2COO)2.6H2O) in different solvents: distilled water, absolute ethanol (C2H5OH), and isopropanol (C3H7OH). The ZnO nanopowders structure was characterized by X-ray powder diffraction (XRD). Raman scattering studies confirm that the as-synthesized nanopowders are of high crystalline quality. High-resolution transmission electron microscopy analysis reveals that the ...

  • 113.pdf.jpg
  • Article


  • Authors: Ta, Dinh Canh; Nguyen, Viet Tuyen; Nguyen, Ngoc Long; Vo, Ly Thanh Ha (2010)

  • n-ZnO:hVp-Si heterojunctions have been fabricated by sputter deposition of nZnO:ln on p-Si substrates. The lowest resistivity n-ZnO:In film was obtained at a substrate temperature of 150oC using a ZnO target doped with 2 wt% In2O3. At substrate temperature above 300oC the resistivity of the film increases as the carrier concentration decreases. This implies a significant decrease in the donor impurity, which is ascribed to evaporation of the indium during film growth. The wavelength dependent properties of the photo-response for the heterojunction were investigated in detail by studying the effect of light illumination on current - voltage (I-V) characteristic, photocurrent spectra ...

  • TL2.pdf.jpg
  • Article


  • Authors: Tran, Thi Ha; Bui, Thi Huyen; Nguyen, Viet Tuyen (2016)

  • Well-aligned CuO nanorods were successfully prepared by thermal oxidation method. The effect of annealing time and annealing temperature on the morphology of the nanorods were studied by scanning electron microscopy. The results show that annealing temperature plays a more critical role in affecting the diameter and density of nanorods. Besides SEM images, the effect of annealing time and temperatures on the structure of the product were also studied by X-ray diffraction and Raman spectroscopy. The diameter of CuO nanorods varies from 30 nm to above 100 nm when annealing temperature changes from 400 °C to 600 °C, while the length of the rods is up to several tens of micrometers. The...

  • 123.pdf.jpg
  • Article


  • Authors: Tran, Thi Ha; Nguyen, Manh Hong; Mai, Hong Hanh; Pham, Van Thanh; Sai, Cong Doanh; Nguyen, Thanh Binh; Pham, Nguyen Hai; Nguyen, Trong Tam; Ho, Khac Hieu; Nguyen, Viet Tuyen (2020)

  • Thanks to unique Raman spectra of chemical substances, a growing number of applications in environmental and biomedical fields based on Raman scattering has been developed. However, the low probability of Raman scattering hindered its potential development and thus, many different techniques were developed to enhance Raman signal. A key step of surface-enhanced Raman scattering technique is to prepare active SERS substrate from noble metals. The main enhancement mechanism is electromagnetic enhancement resulted from surface plasmon resonance. The disadvantages of nanoparticles based SERS substrates include high randomness due to self - assembly process of nanoparticles. Recentl...

  • 7.pdf.jpg
  • Article


  • Authors: Mai, Hong Hanh; Nguyen, Viet Tuyen; Pham, Van Thanh; Hoang, Chi Hieu (2017)

  • High quality, high density, and well-aligned zinc oxide (ZnO) nanorods have been synthesized on cost-effective printed circuit board (PCB) substrates via a simple, seedless, one-step, low-temperature hydrothermal method based galvanic cell structure. It was found that the outer diameters of the ZnO nanorods range from 50 nm to 400 nm. The as-grown ZnO nanorods prefer to grow along the c axis. The morphologies of the ZnO nanorods were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The crystallinity properties were characterized by Raman spectroscopy and photoluminescence (PL) spectroscopy.

Browsing by Author Nguyen, Viet Tuyen

Jump to: 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
or enter first few letters:  
Showing results 1 to 10 of 10
  • 4365-97-9282-1-10-20191218.pdf.jpg
  • Article


  • Authors: Tran, Thi Ngoc Anh; Tran, Thi Ha; Nguyen, Viet Tuyen; Pham, Nguyen Hai (2019)

  • This paper presents results of preparation of Ag doped ZnO bulk sample by solid state reaction and Ag doped ZnO thin films by sputtering method. Effect of doping concentration (1, 2 and 4%) on the properties of the thin films was investigated. Various methods were utilized to investigate characteristics of the samples: X-ray diffraction, Raman scattering spectroscopy, photoluminescence, energy dispersive X-Ray spectroscopy, scanning electron microscopy, atomic force microscope, absorption spectroscopy and Hall measurement. The results show that Ag diffused into ZnO crystal lattice after heat treatment at 1200oC. As-prepared thin film samples exhibit low resistivity in the order of 10-...

  • Effect of Annealing Temperature on Cu2O Thin Films Prepared by Thermal Oxidation Method.pdf.jpg
  • Article


  • Authors: Tran, Thi Ha; Nguyen, Thi Huyen Trang; Bach, Thanh Cong; Nguyen, Thi Dieu Thu; Nguyen, Thanh Binh; Nguyen, Viet Tuyen; Pham, Nguyen Hai (2020)

  • We report a facile process to fabricate cuprous thin films by thermal oxidation of copper substrates. Structure and phase identification were studied by X-ray diffraction measurement and Raman spectroscopy. Scanning electron microscopy was utilized to study surface morphology of the as-fabricated thin films and optical properties of the samples were investigated by diffused reflectance spectroscopy. The study shows that cuprous thin films could be obtained by controlling annealing temperature in the region of 200-300 oC.

  • 4280-97-8419-1-10-20180924.pdf.jpg
  • Article


  • Authors: Pham, Thi Hong; Nguyen, Viet Tuyen; Tran, Thi Ha (2018)

  • Cu2ZnSnS4 (CZTS) is a p-type semiconductor with high absorption coefficient and direct bandgap from 1 to 1.5 eV, which is ideal for making absorber layer for solar cell. However, it is difficult to get single phase of CZTS due to the competitive formation of binary and ternary secondary phases. In this paper, we prepared CZTS nanoparticles by hydrothermal method and investigate the influence of hydrothermal temperature on the product. Raman scattering, X-ray diffraction, scanning electron microcopy, energy dispersive X-ray spectroscopy and diffusion reflective measurement were applied to characterize the products. The products are high quality nanocrystals of kesterite phase with unif...

  • 21.pdf.jpg
  • Article


  • Authors: Nguyen, Viet Tuyen; Tran, Thi Hai; Nguyen, Thi Hong; Phan, Thi Thanh Hong; Ho, Khac Hieu (2017)

  • The anharmonic correlated Debye model has been developed to investigate the pressure effects on the extended X-ray absorption fine structure (EXAFS) Debye-Waller factors of metals. The recent well-established Grüneisen parameter expressions have been applied to formulate the pressure-dependent analytical expressions of the effective spring constant, correlated Debye frequency and temperature. Combing with the anharmonic correlated Debye model, the expression of EXAFS Debye–Waller factor under pressure can be derived. Numerical calculations, performed for Fe and Cu metals show reasonable agreement with experiments.

  • 98.pdf.jpg
  • Article


  • Authors: Ta, Dinh Canh; Nguyen, Viet Tuyen; Nguyen, Ngoc Long (2009)

  • A simple and rapid process has been developed for preparation of nanometer-sized ZnO powders via microwave irradiation, by which ZnO powders with an average particle size of 10-12 nm and narrow size distribution can be synthesized in a short time. We have synthesized ZnO nanoparticles by precipitation from zinc acetate (Zn(CH2COO)2.6H2O) in different solvents: distilled water, absolute ethanol (C2H5OH), and isopropanol (C3H7OH). The ZnO nanopowders structure was characterized by X-ray powder diffraction (XRD). Raman scattering studies confirm that the as-synthesized nanopowders are of high crystalline quality. High-resolution transmission electron microscopy analysis reveals that the ...

  • 113.pdf.jpg
  • Article


  • Authors: Ta, Dinh Canh; Nguyen, Viet Tuyen; Nguyen, Ngoc Long; Vo, Ly Thanh Ha (2010)

  • n-ZnO:hVp-Si heterojunctions have been fabricated by sputter deposition of nZnO:ln on p-Si substrates. The lowest resistivity n-ZnO:In film was obtained at a substrate temperature of 150oC using a ZnO target doped with 2 wt% In2O3. At substrate temperature above 300oC the resistivity of the film increases as the carrier concentration decreases. This implies a significant decrease in the donor impurity, which is ascribed to evaporation of the indium during film growth. The wavelength dependent properties of the photo-response for the heterojunction were investigated in detail by studying the effect of light illumination on current - voltage (I-V) characteristic, photocurrent spectra ...

  • TL2.pdf.jpg
  • Article


  • Authors: Tran, Thi Ha; Bui, Thi Huyen; Nguyen, Viet Tuyen (2016)

  • Well-aligned CuO nanorods were successfully prepared by thermal oxidation method. The effect of annealing time and annealing temperature on the morphology of the nanorods were studied by scanning electron microscopy. The results show that annealing temperature plays a more critical role in affecting the diameter and density of nanorods. Besides SEM images, the effect of annealing time and temperatures on the structure of the product were also studied by X-ray diffraction and Raman spectroscopy. The diameter of CuO nanorods varies from 30 nm to above 100 nm when annealing temperature changes from 400 °C to 600 °C, while the length of the rods is up to several tens of micrometers. The...

  • 123.pdf.jpg
  • Article


  • Authors: Tran, Thi Ha; Nguyen, Manh Hong; Mai, Hong Hanh; Pham, Van Thanh; Sai, Cong Doanh; Nguyen, Thanh Binh; Pham, Nguyen Hai; Nguyen, Trong Tam; Ho, Khac Hieu; Nguyen, Viet Tuyen (2020)

  • Thanks to unique Raman spectra of chemical substances, a growing number of applications in environmental and biomedical fields based on Raman scattering has been developed. However, the low probability of Raman scattering hindered its potential development and thus, many different techniques were developed to enhance Raman signal. A key step of surface-enhanced Raman scattering technique is to prepare active SERS substrate from noble metals. The main enhancement mechanism is electromagnetic enhancement resulted from surface plasmon resonance. The disadvantages of nanoparticles based SERS substrates include high randomness due to self - assembly process of nanoparticles. Recentl...

  • 7.pdf.jpg
  • Article


  • Authors: Mai, Hong Hanh; Nguyen, Viet Tuyen; Pham, Van Thanh; Hoang, Chi Hieu (2017)

  • High quality, high density, and well-aligned zinc oxide (ZnO) nanorods have been synthesized on cost-effective printed circuit board (PCB) substrates via a simple, seedless, one-step, low-temperature hydrothermal method based galvanic cell structure. It was found that the outer diameters of the ZnO nanorods range from 50 nm to 400 nm. The as-grown ZnO nanorods prefer to grow along the c axis. The morphologies of the ZnO nanorods were investigated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The crystallinity properties were characterized by Raman spectroscopy and photoluminescence (PL) spectroscopy.