Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize th...Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize the effect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP （O-ICP）＇s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP （CI-ICP）, the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP＇s treatment, while the work function after Cl-ICP＇s treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more effective than CI-ICP for enhancing the work function of AZO films, which is well consistent with KP results.展开更多
We propose and demonstrate a passively mode-locked erbium-doped fiber laser(EDFL)based on zinc-oxide/polydimethylsiloxane(ZnO/PDMS)saturable absorber(SA)that evanescently interacts with the light on a tapered fiber.Th...We propose and demonstrate a passively mode-locked erbium-doped fiber laser(EDFL)based on zinc-oxide/polydimethylsiloxane(ZnO/PDMS)saturable absorber(SA)that evanescently interacts with the light on a tapered fiber.The ZnO/PDMS composite is coated on the whole surface of the tapered fiber to guarantee the maximum efficiency of the SA device,with a measured insertion loss of 0.87 dB and a modulation depth of 6.4%.The proposed laser can generate soliton mode-locking operation at a threshold power of 33.07 mW.The generated output pulse yields a repetition rate and pulse width of 9.77 MHz and 1.03 ps,respectively.These results indicate that the proposed ZnO/PDMS-clad tapered fiber could be useful as an efficient,compatible,and low-cost SA device for ultrafast laser applications.展开更多
We report that the composites of ZnO/porous Si （PS） can exhibit intensively white photoluminescence （PL） under proper excitation wavelength. The PS sample is formed by electrochemical anodization of n-type （111）...We report that the composites of ZnO/porous Si （PS） can exhibit intensively white photoluminescence （PL） under proper excitation wavelength. The PS sample is formed by electrochemical anodization of n-type （111） silicon. ZnO films are then deposited on the PS surface by pulsed laser deposition （PLD）. ZnO is transparent in the visible region, so the red PL from PS can be transmitted through the ZnO films. White PL from the ZnO layer on PS can be obtained, which consists of blue-green emission from ZnO and red emission from PS. The x-ray diffraction （XRD） pattern shows that the ZnO films deposited on PS surface are non-crystalline. Due to the roughness of the PS surface, some cracks appear in the ZnO films, which could be seen from the scanning electron microscopy （SEM） images.展开更多
Zn0.99Co0.01O nano-needles are synthesized by using pure ZnO powder as the starting material via chemical reactions in ammonia aqueous solution. The nano-needles show the room-temperature ferromagnetism （RTFM） chara...Zn0.99Co0.01O nano-needles are synthesized by using pure ZnO powder as the starting material via chemical reactions in ammonia aqueous solution. The nano-needles show the room-temperature ferromagnetism （RTFM） characterized by using a superconducting quantum interference device. Non-reductive chemical synthesis steps ensure to prevent forming Co-metal nanoclusters within the doped sample. All the results of thermal gravimetric analysis, Fourier transform infrared spectroscopy, x-ray diffraction and ultraviolet spectroscopy demonstrate that Co ions have doped into ZnO lattices and occupied some Zn sites without changing the wurtzite structure of ZnO lattices, and no potential second phase except for the doped Co ions substituting the Zn sites in ZnO lattice can account for the observed RTFM behaviour. Moreover, the synthesis process is of high reproducibility over 80% which is higher than that of commonly-used sol-gel method.展开更多
Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon （PS） using a simple vapour-solid （VS） growth method. A comparison of their morphologies is ...Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon （PS） using a simple vapour-solid （VS） growth method. A comparison of their morphologies is investigated by scanning electron microscopy （SEM）. The transmission electron microscopy （TEM） confirms that ZnO nanobelts and nanorods are single crystalline with the growth direction of （0110） and （0001）, respectively. Field emission tests indicate that the ZnO nanostructures on porous silicon have low turn-on field of about 3.6 V/μm （at 1.0μA/cm^2） and the threshold field of about 8.3 V/μm （at 1.0mA/cm^2）, high emission site density （ESD） of approximately 104 cm^-2.展开更多
We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-（3′, 7′-dimethyloctyloxy）- 1,4-phenylenevinylene] （MDMO-PPV） bulk heterojunction photovoltaic cells. Photoluminescence quenchin...We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-（3′, 7′-dimethyloctyloxy）- 1,4-phenylenevinylene] （MDMO-PPV） bulk heterojunction photovoltaic cells. Photoluminescence quenching experimental results indicate that the ultrafast photoinduced electron transfer occurs from MDMO-PPV to ZnO under illumination. The ultrafast photoinduced electron transfer effect is induced because ZnO has an electron affinity a bout 1.2 e V greater than that of MDMO-PP V. Electron ＇back transfer＇ can occur if the interfacial barrier between ZnO and MDMO-PPV can be overcome by applying a substantial electric field. Therefore, electrolumi- nescence action due to the fact that the back transfer effect can be observed in the ZnO：MDMO-PPV devices since a forward bias is applied. The photovoltaic and electroluminescence actions in the same ZnO：MDMO-PPV device can be induced by different injection ways： photoinjection and electrical injection. The devices are expected to provide an opportunity for dual functionality devices with photovoltaic effect and electroluminescence character.展开更多
Different photoluminescence （PL） spectra are observed for rf magnetron sputtered polycrystalline Mg0.25Zn0.75O and Mg0.37Zn0.63O films on silicon substrates when excited by different wavelengths. When the excitation...Different photoluminescence （PL） spectra are observed for rf magnetron sputtered polycrystalline Mg0.25Zn0.75O and Mg0.37Zn0.63O films on silicon substrates when excited by different wavelengths. When the excitation wavelength is 280nm, a UV emission peak at 370nm and a blue peak at 462nm are generated for the Mg0.25Zn0.75O film, and those two peaks for the Mg0.37Zn0.63O film shift to 366nm and 466nm, respectively. The wavelengths of the PL peaks are related to the excitation wavelength. The stronger peak is obtained in the blue band due to a large number of oxygen vacancies caused by excess Zn and Mg atoms, while the weaker peak is obtained in the ultraviolet band.展开更多
ZnO nanorods are fabricated by arc discharge with ZnO powder as source materials. The sample is characterized by x-ray diffraction, Raman scattering spectra, scanning electron microscopy and high-resolution transmissi...ZnO nanorods are fabricated by arc discharge with ZnO powder as source materials. The sample is characterized by x-ray diffraction, Raman scattering spectra, scanning electron microscopy and high-resolution transmission electron microscopy. The ZnO nanorods exhibit single crystals with the hexagonal wurtzite structure. Many of them are tetrapod-like. The diameters range from several nanometres to about lOOnm, and the main diameters of the nanorods is around 20nm. The length-to-diameter ratio is more than 5, and the grown directions are along the [001] axis. Photoluminescence spectra show a narrow ultraviolet emission at around 389nm and a broad green emission at around 520 nm. The growth process can be interpreted by the vapour-solid mechanism.展开更多
Undoped and copper doped zinc oxide （ZnO） thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt （CuCl2...Undoped and copper doped zinc oxide （ZnO） thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt （CuCl2） in the spray solution of ZnO. Variation of structural, electrical, optical and thermoluminescence （TL） properties with doping concentrations is investigated in detail.展开更多
Piezoelectric nanowires have attracted much scientific interest in the last few years because of their enhanced piezoelectric coefficients at nanometer scale, with promises of efficient mechanical energy harvesters fo...Piezoelectric nanowires have attracted much scientific interest in the last few years because of their enhanced piezoelectric coefficients at nanometer scale, with promises of efficient mechanical energy harvesters for autonomous integrated systems. This paper presents the design and, for the first time, guideline rules, based on simple analytical expressions, to improve the performance of a mechanical energy harvester integrating vertical ZnO piezoelectric nanowires. Additional simulations were carried out to account more realistically for device geometry. The authors discuss the prospects of such an approach, based on design and material improvement.展开更多
基金supported by National Natural Science Foundation of China(Nos.1100502151177017 and 11175049)+1 种基金the Fudan University Excellent Doctoral Research Program(985 Project) the Ph.D Programs Foundation of Ministry of Education of China(No.20120071110031)
文摘Al-doped zinc-oxide （AZO） thin films treated by oxygen and chlorine inductively coupled plasma （ICP） were compared. Kelvin probe （KP） and X-ray photoelectron spectroscopy （XPS） were employed to characterize the effect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP （O-ICP）＇s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP （CI-ICP）, the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP＇s treatment, while the work function after Cl-ICP＇s treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more effective than CI-ICP for enhancing the work function of AZO films, which is well consistent with KP results.
基金the Ministry of Higher Education of Malaysia(MOHE)(Grant No.FRGS/1/2019/STG02/UPM/02/4).
文摘We propose and demonstrate a passively mode-locked erbium-doped fiber laser(EDFL)based on zinc-oxide/polydimethylsiloxane(ZnO/PDMS)saturable absorber(SA)that evanescently interacts with the light on a tapered fiber.The ZnO/PDMS composite is coated on the whole surface of the tapered fiber to guarantee the maximum efficiency of the SA device,with a measured insertion loss of 0.87 dB and a modulation depth of 6.4%.The proposed laser can generate soliton mode-locking operation at a threshold power of 33.07 mW.The generated output pulse yields a repetition rate and pulse width of 9.77 MHz and 1.03 ps,respectively.These results indicate that the proposed ZnO/PDMS-clad tapered fiber could be useful as an efficient,compatible,and low-cost SA device for ultrafast laser applications.
基金Supported by the Natural Science Foundation of Shandong Province under Grant No Y2002A09.
文摘We report that the composites of ZnO/porous Si （PS） can exhibit intensively white photoluminescence （PL） under proper excitation wavelength. The PS sample is formed by electrochemical anodization of n-type （111） silicon. ZnO films are then deposited on the PS surface by pulsed laser deposition （PLD）. ZnO is transparent in the visible region, so the red PL from PS can be transmitted through the ZnO films. White PL from the ZnO layer on PS can be obtained, which consists of blue-green emission from ZnO and red emission from PS. The x-ray diffraction （XRD） pattern shows that the ZnO films deposited on PS surface are non-crystalline. Due to the roughness of the PS surface, some cracks appear in the ZnO films, which could be seen from the scanning electron microscopy （SEM） images.
基金Supported by the National Natural Science Foundation of China under Grant No 20401001, the Key Project of Anhui Provincial Science and Technology Department under Grant No 04022075, the Project of Anhui Provincial Educational Department under Grant No 2004jq113, and the Fund of Laboratory of Solid State Microstructures, Nanjing University under Grant No M031803.
文摘Zn0.99Co0.01O nano-needles are synthesized by using pure ZnO powder as the starting material via chemical reactions in ammonia aqueous solution. The nano-needles show the room-temperature ferromagnetism （RTFM） characterized by using a superconducting quantum interference device. Non-reductive chemical synthesis steps ensure to prevent forming Co-metal nanoclusters within the doped sample. All the results of thermal gravimetric analysis, Fourier transform infrared spectroscopy, x-ray diffraction and ultraviolet spectroscopy demonstrate that Co ions have doped into ZnO lattices and occupied some Zn sites without changing the wurtzite structure of ZnO lattices, and no potential second phase except for the doped Co ions substituting the Zn sites in ZnO lattice can account for the observed RTFM behaviour. Moreover, the synthesis process is of high reproducibility over 80% which is higher than that of commonly-used sol-gel method.
基金Supported by the National Natural Science Foundation of China under Grant No 60476004, the Foundation of State Key Laboratory of Advanced Technology for Materials Synthesis and Processing of Wuhan University of Technology under Grant No WUT2004 Z01, and GS of ECNU （No ECNU 2005）.
文摘Mass production of ZnO nanobelts and hexagonal nanorods has been successfully synthesized on CuO catalyzed porous silicon （PS） using a simple vapour-solid （VS） growth method. A comparison of their morphologies is investigated by scanning electron microscopy （SEM）. The transmission electron microscopy （TEM） confirms that ZnO nanobelts and nanorods are single crystalline with the growth direction of （0110） and （0001）, respectively. Field emission tests indicate that the ZnO nanostructures on porous silicon have low turn-on field of about 3.6 V/μm （at 1.0μA/cm^2） and the threshold field of about 8.3 V/μm （at 1.0mA/cm^2）, high emission site density （ESD） of approximately 104 cm^-2.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60476002, 60390071, 60576036 and 60276014, the National Basic Research Programme of China under Grant Nos 2006CB202604 and 2006CB604900, and the Hi-Tech Research and Development Programme of China under Grant No 2006AA03Z0408.
文摘We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-（3′, 7′-dimethyloctyloxy）- 1,4-phenylenevinylene] （MDMO-PPV） bulk heterojunction photovoltaic cells. Photoluminescence quenching experimental results indicate that the ultrafast photoinduced electron transfer occurs from MDMO-PPV to ZnO under illumination. The ultrafast photoinduced electron transfer effect is induced because ZnO has an electron affinity a bout 1.2 e V greater than that of MDMO-PP V. Electron ＇back transfer＇ can occur if the interfacial barrier between ZnO and MDMO-PPV can be overcome by applying a substantial electric field. Therefore, electrolumi- nescence action due to the fact that the back transfer effect can be observed in the ZnO：MDMO-PPV devices since a forward bias is applied. The photovoltaic and electroluminescence actions in the same ZnO：MDMO-PPV device can be induced by different injection ways： photoinjection and electrical injection. The devices are expected to provide an opportunity for dual functionality devices with photovoltaic effect and electroluminescence character.
文摘Different photoluminescence （PL） spectra are observed for rf magnetron sputtered polycrystalline Mg0.25Zn0.75O and Mg0.37Zn0.63O films on silicon substrates when excited by different wavelengths. When the excitation wavelength is 280nm, a UV emission peak at 370nm and a blue peak at 462nm are generated for the Mg0.25Zn0.75O film, and those two peaks for the Mg0.37Zn0.63O film shift to 366nm and 466nm, respectively. The wavelengths of the PL peaks are related to the excitation wavelength. The stronger peak is obtained in the blue band due to a large number of oxygen vacancies caused by excess Zn and Mg atoms, while the weaker peak is obtained in the ultraviolet band.
基金Supported by the National Natural Science Foundation of China under Grant No 60576008, and the Doctoral Programme High Education （20050286004）.
文摘ZnO nanorods are fabricated by arc discharge with ZnO powder as source materials. The sample is characterized by x-ray diffraction, Raman scattering spectra, scanning electron microscopy and high-resolution transmission electron microscopy. The ZnO nanorods exhibit single crystals with the hexagonal wurtzite structure. Many of them are tetrapod-like. The diameters range from several nanometres to about lOOnm, and the main diameters of the nanorods is around 20nm. The length-to-diameter ratio is more than 5, and the grown directions are along the [001] axis. Photoluminescence spectra show a narrow ultraviolet emission at around 389nm and a broad green emission at around 520 nm. The growth process can be interpreted by the vapour-solid mechanism.
文摘Undoped and copper doped zinc oxide （ZnO） thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt （CuCl2） in the spray solution of ZnO. Variation of structural, electrical, optical and thermoluminescence （TL） properties with doping concentrations is investigated in detail.
文摘Piezoelectric nanowires have attracted much scientific interest in the last few years because of their enhanced piezoelectric coefficients at nanometer scale, with promises of efficient mechanical energy harvesters for autonomous integrated systems. This paper presents the design and, for the first time, guideline rules, based on simple analytical expressions, to improve the performance of a mechanical energy harvester integrating vertical ZnO piezoelectric nanowires. Additional simulations were carried out to account more realistically for device geometry. The authors discuss the prospects of such an approach, based on design and material improvement.
