Browsing by Author Nguyen, Ngoc Long

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  • 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 ...

  • 62.pdf.jpg
  • Article


  • Authors: Trinh, Thi Loan; Nguyen, Ngoc Long (2014)

  • Anatase TiO2 powders doped with 0.5, 1.0, 4.0 and 10 mol% Cr3+ have been prepared by hydrothermal method. The Cr3+ concentration and annealing effects on crystalline structure, absorption and photoluminescent spectra of the synthesized samples have been investigated. The band gap energy of anatase and rutile TiO2:Cr3+ powders with different dopant contents has been determined. Urbach energies (Eu) characterized for the structural disorder in the anatase and rutile TiO2 host lattice doped with Cr3+ ions also have been calculated with different impurity concentrations. At low annealing temperature (≤ 600 oC), the samples exhibited anatase phase and the photoluminescent spectra consisted...

  • 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 ...

  • 149.pdf.jpg
  • Article


  • Authors: Vu, Thi Thai Ha; Nguyen, Thi Quy Hai; Nguyen, Ngoc Long; Le, Van Vu (2007)

  • L ithium Auoride (LiF) thermolum inescent powder doped with Mg, Cu, Na, and Si as activators was prepared. X-ray diffraction analysis indicated that doping LiF vvith different activators m akes crystal lattice som ew hat expand. The dosimetric properties o f the powder were studied. The main dosimetric peak of LiF:Mg,Cu,Na,Si appeared in the range of 227 - 247°C and the ratio of the height of the main peak to that of the other small peaks in the LiF:Mg,Cu,Na,Si is much greater than that in the LiF:Mg,Ti and LiF:Mg,Cu,P. The preparation conditions such as annealing temperature and duration, annealing atmosphere, doping vvith different activators etc. were investigated.

  • 25.pdf.jpg
  • Article


  • Authors: Duong, Thi Mai Huong; Le, Van Vu; Nguyen, Ngoc Long; Duong, Ngoc Thanh (2016)

  • CaF2nanoparticles doped with 0, 1, 2, 3, 4 and 5 mol% Sm3+ were prepared by co-precipitation method. These nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescence excitation (PLE) spectra, energy-dispersive X-ray spectroscopy (EDS) and diffuse reflective spectra. The XRD patterns indicate cubic structure of CaF2 and no other impurities. TEM images show that CaF2 nanoparticles have size varying from 15 to 20 nm. The photoluminescence spectra show 4 peaks at 566 nm, 604 nm, 645 nm and 704 nm, which are assigned to different transitions from the 4G(4)5/2 excited state to the 6HJ with J = 5/2; 7/2; 9/2 and ...

  • 40.pdf.jpg
  • Article


  • Authors: Pham, Thi Thanh Hien; Duong, Thi Mai Huong; Nguyen, Ngoc Long; Le, Van Vu; Hoang, Manh Ha (2015)

  • LaPO4 nanowires doped with 1, 2,…8 mol% Sm3+ were prepared by a hydrothermal method. The samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL), photoluminescence excitation (PLE), and absorption (ABS) spectroscopy. It was discovered that the PL and PLE of Sm3+ ions resulted from the radiative intra-configurational f-f transitions. The photoluminescence spectra shows 4 peaks at 560 nm, 596 nm, 642 nm and 701 nm which were assigned to different transitions from the 4G (4)5/2 excited state to the 6HJ with J = 5/2; 7/2; 9/2; 11/2 ground states of Sm3+ ion. The intensity of PL related to Sm3+ ion reached to a maximum when the ...

  • 124.pdf.jpg
  • Article


  • Authors: Nguyen, Hoang Luong; Nguyen, Ngoc Long; Le, Van Vu; Nguyen, Hoang Hai; Luu, Manh Quynh (2009)

  • Sphere-like gold nanoparticles have been prepared by chemical reduction method and by using X-ray irradiation, while rod-like gold nanoparticles were synthesized according to the seed-mediated growth method and by sonoelectrochemistry. Sphere-like gold nanoparticles have diameter of 20 - 60 nm, while rod-like gold nanoparticles have aspect ratio from 2 to 4. In UV-vis spectra the absorption bands related to surface piasmon resonance were observed. CoPt nanoparticlcs with the size of 5 - 20 nm have been prepared by electrodeposition, while FePt Iianoparticles with the size of 5 - 10 nm were synthesized by sonoclectrodeposition. After annealing, these magnetic nanoparticles showed a hig...

  • item.jpg
  • Article


  • Authors: Trinh, Thi Loan; Nguyen, Ngoc Long (2018)

  • Anatase TiO2 powders doped with different amounts of Cu2+ ions (0, 0.5, 1.0 and 4 mol%) were successfully synthesized by sol-gel method from precursors of TiCl4, (CH3COO)2Cu. Effect of Cu2+ concentrations on the structural and optical properties of TiO2 host was investigated by X-ray diffraction, Raman spectroscopy and diffuse reflection spectroscopy. The XRD analysis showed that the doped samples exhibit anatase single phase at annealing temperature 600 oC. The Cu2+ contents did not affect on the lattice of TiO2 hot, but affected on positions of these Raman modes. The band gap of the TiO2:Cu2+ was decreased with the increase of doping concentration.

  • 74.pdf.jpg
  • Article


  • Authors: Ho, Minh Trung; Nguyen, Duy Thien; Duong, Thi Lien; Nguyen, Ngoc Long; Le, Van Vu (2011)

  • In this paper, we present the results on synthesis of indium nanoparticles by the reduction of indium chloride in a solution of sodium borohydride (NaBH4). The indium nanoparticles were characterized by X-ray diffraction, transmission electron microscopy (TEM) and UV-visible spectroscopy. The analysis of X-ray diffraction (XRD) indicates that the indium nanoparticles possess a tetragonal crystal structure. The TEM images demonstrate that the nanoparticles with a size about 100 nm were agglomerate from many smaller particles. Effect of some technology conditions on the formation of the indium nanoparticles was studied.

  • TL11.pdf.jpg
  • Article


  • Authors: Trinh, Thi Loan; Tran, Thi Dung; Vu, Hoang Huong; Nguyen, Ngoc Long (2016)

  • TiO2 nanowires doped with different amounts of Ni2+ ions (from 0 to 18 mol%) were synthesized by hydrothermal technique. The samples were characterized by X-ray diffraction (XRD) and Raman spectroscopy, field emission scanning electron microscopy (FESEM), and diffuse reflection spectroscopy. The XRD analysis showed that the doped samples exhibit anatase single phase. The lattice parameters remain unchanged, independent on Ni2+ content. Diameter of TiO2 nanowires increased significantly with increasing concentrations of Ni2+. The investigated results indicate that a greater portion of the Ni2+ ions are well-incorporated into the anatase TiO2 lattice. Indirect and direct band gap energi...

  • 41.pdf.jpg
  • Article


  • Authors: Duong, Thi Mai Huong; Nguyen, Thi Tien; Le, Van Vu; Nguyen, Ngoc Long (2015)

  • CeF3nanoparticles doped with 0; 1.0; 1.5; 2.0; 2.5; 3.0 and 4.0 mol% Sm3+ were prepared by co-precipitation technique. These nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescence excitation (PLE) spectra, energy-dispersive X-ray (EDS) and absorption spectra. The PL spectra exhibit a group of four emission lines, which are assigned to the transitions from the excited state 4G5/2 to the ground states 6HJ with J = 5/2; 7/2; 9/2 and 11/2 of Sm3+ ion. The intensity of PL related to Sm3+ ion reached to a maximum when the Sm dopant content was 2 mol%. The PLE spectra show 8 lines, which are attributed to the a...

  • 4253-97-8268-1-10-20180320.pdf.jpg
  • Article


  • Authors: Trinh, Thi Loan; Nguyen, Ngoc Long (2018)

  • Zinc aluminate - alumina (ZnAl2O4/Al2O3) systems doped with Cr3+ different concentrations were synthesized by sol-gel method. The samples were characterized by X-ray diffraction (XRD), photoluminescence (PL) and photoluminescence excitation (PLE) spectra. The results showed that Cr3+ dopant concentration had a significant effect on the lattice constants of ZnAl2O4/Al2O3 composite and their luminescence characteristics.

  • 01050000344.pdf.jpg
  • Thesis


  • Authors: Nguyen, Duy Thien;  Advisor: Nguyen, Ngoc Long (2011)

  • Tổng quan về vật liệu vàng: trình bầy về các tính chất vật lý hóa học cơ bản, các dạng hình thái thường gặp, các tính chất đặc trưng như tính chất điện, tính chất từ, tính chất nhiệt và tính chất quang với hiệu ứng plasmon bề mặt đặc trưng của vật liệu nano vàng; trình bày sơ lược về hướng ứng dụng của nano vàng trong y sinh học. Nghiên cứu các phương pháp thực nghiệm: giới thiệu về các phương pháp thực nghiệm thường được dùng để tổng hợp vật liệu nano vàng; trình bầy về phương pháp điện hóa siêu âm để tổng hợp vật liệu nano vàng và các phương pháp phân tích kết quả được sử dụng. Trình bày kết quả và thảo luận: trình bầy về các kết quả thu được trong quá trình thực nghiệm tổng hợp vật...

  • 197.pdf.jpg
  • Article


  • Authors: Ngac, An Bang; Nguyen, Ngoc Long (2004)

  • Single-crystalline zinc oxide (ZnO) whiskers were successfully synthesized on the Si/Si02 substrates by therm ally evaporating metal zinc powders at tem peratures of 600 and 650°c . EDS microanalysis and XRD measurement showed that the product w as single-crystalline ZnO with a hexagonal w urtzite structure. SEM analysis revealed that the synthesized ZnO whiskers have an average diameter of 200 nm and typical lengths of up to 1 àm.

Browsing by Author Nguyen, Ngoc Long

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 4 to 18 of 18
  • 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 ...

  • 62.pdf.jpg
  • Article


  • Authors: Trinh, Thi Loan; Nguyen, Ngoc Long (2014)

  • Anatase TiO2 powders doped with 0.5, 1.0, 4.0 and 10 mol% Cr3+ have been prepared by hydrothermal method. The Cr3+ concentration and annealing effects on crystalline structure, absorption and photoluminescent spectra of the synthesized samples have been investigated. The band gap energy of anatase and rutile TiO2:Cr3+ powders with different dopant contents has been determined. Urbach energies (Eu) characterized for the structural disorder in the anatase and rutile TiO2 host lattice doped with Cr3+ ions also have been calculated with different impurity concentrations. At low annealing temperature (≤ 600 oC), the samples exhibited anatase phase and the photoluminescent spectra consisted...

  • 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 ...

  • 149.pdf.jpg
  • Article


  • Authors: Vu, Thi Thai Ha; Nguyen, Thi Quy Hai; Nguyen, Ngoc Long; Le, Van Vu (2007)

  • L ithium Auoride (LiF) thermolum inescent powder doped with Mg, Cu, Na, and Si as activators was prepared. X-ray diffraction analysis indicated that doping LiF vvith different activators m akes crystal lattice som ew hat expand. The dosimetric properties o f the powder were studied. The main dosimetric peak of LiF:Mg,Cu,Na,Si appeared in the range of 227 - 247°C and the ratio of the height of the main peak to that of the other small peaks in the LiF:Mg,Cu,Na,Si is much greater than that in the LiF:Mg,Ti and LiF:Mg,Cu,P. The preparation conditions such as annealing temperature and duration, annealing atmosphere, doping vvith different activators etc. were investigated.

  • 25.pdf.jpg
  • Article


  • Authors: Duong, Thi Mai Huong; Le, Van Vu; Nguyen, Ngoc Long; Duong, Ngoc Thanh (2016)

  • CaF2nanoparticles doped with 0, 1, 2, 3, 4 and 5 mol% Sm3+ were prepared by co-precipitation method. These nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescence excitation (PLE) spectra, energy-dispersive X-ray spectroscopy (EDS) and diffuse reflective spectra. The XRD patterns indicate cubic structure of CaF2 and no other impurities. TEM images show that CaF2 nanoparticles have size varying from 15 to 20 nm. The photoluminescence spectra show 4 peaks at 566 nm, 604 nm, 645 nm and 704 nm, which are assigned to different transitions from the 4G(4)5/2 excited state to the 6HJ with J = 5/2; 7/2; 9/2 and ...

  • 40.pdf.jpg
  • Article


  • Authors: Pham, Thi Thanh Hien; Duong, Thi Mai Huong; Nguyen, Ngoc Long; Le, Van Vu; Hoang, Manh Ha (2015)

  • LaPO4 nanowires doped with 1, 2,…8 mol% Sm3+ were prepared by a hydrothermal method. The samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL), photoluminescence excitation (PLE), and absorption (ABS) spectroscopy. It was discovered that the PL and PLE of Sm3+ ions resulted from the radiative intra-configurational f-f transitions. The photoluminescence spectra shows 4 peaks at 560 nm, 596 nm, 642 nm and 701 nm which were assigned to different transitions from the 4G (4)5/2 excited state to the 6HJ with J = 5/2; 7/2; 9/2; 11/2 ground states of Sm3+ ion. The intensity of PL related to Sm3+ ion reached to a maximum when the ...

  • 124.pdf.jpg
  • Article


  • Authors: Nguyen, Hoang Luong; Nguyen, Ngoc Long; Le, Van Vu; Nguyen, Hoang Hai; Luu, Manh Quynh (2009)

  • Sphere-like gold nanoparticles have been prepared by chemical reduction method and by using X-ray irradiation, while rod-like gold nanoparticles were synthesized according to the seed-mediated growth method and by sonoelectrochemistry. Sphere-like gold nanoparticles have diameter of 20 - 60 nm, while rod-like gold nanoparticles have aspect ratio from 2 to 4. In UV-vis spectra the absorption bands related to surface piasmon resonance were observed. CoPt nanoparticlcs with the size of 5 - 20 nm have been prepared by electrodeposition, while FePt Iianoparticles with the size of 5 - 10 nm were synthesized by sonoclectrodeposition. After annealing, these magnetic nanoparticles showed a hig...

  • item.jpg
  • Article


  • Authors: Trinh, Thi Loan; Nguyen, Ngoc Long (2018)

  • Anatase TiO2 powders doped with different amounts of Cu2+ ions (0, 0.5, 1.0 and 4 mol%) were successfully synthesized by sol-gel method from precursors of TiCl4, (CH3COO)2Cu. Effect of Cu2+ concentrations on the structural and optical properties of TiO2 host was investigated by X-ray diffraction, Raman spectroscopy and diffuse reflection spectroscopy. The XRD analysis showed that the doped samples exhibit anatase single phase at annealing temperature 600 oC. The Cu2+ contents did not affect on the lattice of TiO2 hot, but affected on positions of these Raman modes. The band gap of the TiO2:Cu2+ was decreased with the increase of doping concentration.

  • 74.pdf.jpg
  • Article


  • Authors: Ho, Minh Trung; Nguyen, Duy Thien; Duong, Thi Lien; Nguyen, Ngoc Long; Le, Van Vu (2011)

  • In this paper, we present the results on synthesis of indium nanoparticles by the reduction of indium chloride in a solution of sodium borohydride (NaBH4). The indium nanoparticles were characterized by X-ray diffraction, transmission electron microscopy (TEM) and UV-visible spectroscopy. The analysis of X-ray diffraction (XRD) indicates that the indium nanoparticles possess a tetragonal crystal structure. The TEM images demonstrate that the nanoparticles with a size about 100 nm were agglomerate from many smaller particles. Effect of some technology conditions on the formation of the indium nanoparticles was studied.

  • TL11.pdf.jpg
  • Article


  • Authors: Trinh, Thi Loan; Tran, Thi Dung; Vu, Hoang Huong; Nguyen, Ngoc Long (2016)

  • TiO2 nanowires doped with different amounts of Ni2+ ions (from 0 to 18 mol%) were synthesized by hydrothermal technique. The samples were characterized by X-ray diffraction (XRD) and Raman spectroscopy, field emission scanning electron microscopy (FESEM), and diffuse reflection spectroscopy. The XRD analysis showed that the doped samples exhibit anatase single phase. The lattice parameters remain unchanged, independent on Ni2+ content. Diameter of TiO2 nanowires increased significantly with increasing concentrations of Ni2+. The investigated results indicate that a greater portion of the Ni2+ ions are well-incorporated into the anatase TiO2 lattice. Indirect and direct band gap energi...

  • 41.pdf.jpg
  • Article


  • Authors: Duong, Thi Mai Huong; Nguyen, Thi Tien; Le, Van Vu; Nguyen, Ngoc Long (2015)

  • CeF3nanoparticles doped with 0; 1.0; 1.5; 2.0; 2.5; 3.0 and 4.0 mol% Sm3+ were prepared by co-precipitation technique. These nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), photoluminescence excitation (PLE) spectra, energy-dispersive X-ray (EDS) and absorption spectra. The PL spectra exhibit a group of four emission lines, which are assigned to the transitions from the excited state 4G5/2 to the ground states 6HJ with J = 5/2; 7/2; 9/2 and 11/2 of Sm3+ ion. The intensity of PL related to Sm3+ ion reached to a maximum when the Sm dopant content was 2 mol%. The PLE spectra show 8 lines, which are attributed to the a...

  • 4253-97-8268-1-10-20180320.pdf.jpg
  • Article


  • Authors: Trinh, Thi Loan; Nguyen, Ngoc Long (2018)

  • Zinc aluminate - alumina (ZnAl2O4/Al2O3) systems doped with Cr3+ different concentrations were synthesized by sol-gel method. The samples were characterized by X-ray diffraction (XRD), photoluminescence (PL) and photoluminescence excitation (PLE) spectra. The results showed that Cr3+ dopant concentration had a significant effect on the lattice constants of ZnAl2O4/Al2O3 composite and their luminescence characteristics.

  • 01050000344.pdf.jpg
  • Thesis


  • Authors: Nguyen, Duy Thien;  Advisor: Nguyen, Ngoc Long (2011)

  • Tổng quan về vật liệu vàng: trình bầy về các tính chất vật lý hóa học cơ bản, các dạng hình thái thường gặp, các tính chất đặc trưng như tính chất điện, tính chất từ, tính chất nhiệt và tính chất quang với hiệu ứng plasmon bề mặt đặc trưng của vật liệu nano vàng; trình bày sơ lược về hướng ứng dụng của nano vàng trong y sinh học. Nghiên cứu các phương pháp thực nghiệm: giới thiệu về các phương pháp thực nghiệm thường được dùng để tổng hợp vật liệu nano vàng; trình bầy về phương pháp điện hóa siêu âm để tổng hợp vật liệu nano vàng và các phương pháp phân tích kết quả được sử dụng. Trình bày kết quả và thảo luận: trình bầy về các kết quả thu được trong quá trình thực nghiệm tổng hợp vật...

  • 197.pdf.jpg
  • Article


  • Authors: Ngac, An Bang; Nguyen, Ngoc Long (2004)

  • Single-crystalline zinc oxide (ZnO) whiskers were successfully synthesized on the Si/Si02 substrates by therm ally evaporating metal zinc powders at tem peratures of 600 and 650°c . EDS microanalysis and XRD measurement showed that the product w as single-crystalline ZnO with a hexagonal w urtzite structure. SEM analysis revealed that the synthesized ZnO whiskers have an average diameter of 200 nm and typical lengths of up to 1 àm.