Highly c-axis-oriented ZnO films were deposited successfully on the nucleation sides of free-standing diamond （FD） films by the direct current （DC） magnetron sputtering method. The effect of the sputtering paramet...Highly c-axis-oriented ZnO films were deposited successfully on the nucleation sides of free-standing diamond （FD） films by the direct current （DC） magnetron sputtering method. The effect of the sputtering parameters, such as power, gas pressure and sputtering plasma composition of Ar-to-O2, on the properties of ZnO thin films was investigated in detail. X-ray diffraction （XRD） measurements showed that, at a sputtering power of 200 W, gas pressure of 0.5 Pa and an Ar-to- O2 composition of 1：1, a higher intensity of the （002） diffraction peak and a narrower full width at half maximum （FWHM） were detected which meant high c-axis orientation and high quality of the ZnO films. To improve the quality of the ZnO film, a thin ZnO layer was pre-grown as a homo-buffer layer. XRD measurements showed that this buffer layer had a beneficial effect on the structural and morphological properties of the post-grown ZnO film.展开更多
ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, t...ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, the deep-level transient spectroscopy （DLTS） and the photoluminescence （PL） spectra of the samples were measured. DLTS shows two deep-level centres of E1 （Ec-0.13±0.02eV） and E2 （Ec-0.43±0.05eV） in sample 1202a, which has a ZnO/p-Si heterostructure. A deep level at Ec-0.13±0.01 eV was also obtained from the I -T characteristics. It was considered to be the same as E1 obtained from DLTS measurement. The emission related to this deep level center was detected by PL spectra. In addition, the energy location and the relative trap density of E1 was varied when the total gas flow rate was changed.展开更多
High-quality MgxZn1-xO thin films were grown on sapphire（0001 ） substrates with a ZnO buffer layer of different thicknesses by means of metal-organic chemical vapor deposition. Diethyl zinc, bis-cyclopentadienyl-Mg ...High-quality MgxZn1-xO thin films were grown on sapphire（0001 ） substrates with a ZnO buffer layer of different thicknesses by means of metal-organic chemical vapor deposition. Diethyl zinc, bis-cyclopentadienyl-Mg and oxygen were used as the precursor materials. The crystalline quality, surface morphologies and optical properties of the Mg, Zn1-xO films were investigated by X-ray diffraction, atomic force microscopy and photoluminescence spectrometry. It was shown that the quality of the MgxZn1-xO thin films depends on the thickness of the ZnO buffer layer and an Mg, Zn1-xO thin film with a ZnO buffer layer whose thickness was 20 nm exhibited the best crystal-quality, optical properties and a flat and dense surface.展开更多
ZnO films with low resistivity and high transmittance in the visible optical region were deposited on GaAs and glass substrates by MOCVD at atmospheric pressure using diethyl zinc and tetrahydrofuran as precursors.The...ZnO films with low resistivity and high transmittance in the visible optical region were deposited on GaAs and glass substrates by MOCVD at atmospheric pressure using diethyl zinc and tetrahydrofuran as precursors.The X ray diffraction results revealed that ZnO epilayer on GaAs showed good crystalline character and exhibited (002) orientation with the c axis perpendicular to the substrate surface.The resistivity of ZnO films in the range from 10 -3 ～10 -2 Ω·cm was found to be dependent upon the initial partial pressure of diethyl zinc and tetrahydrofuran.展开更多
ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scan...ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy（SEM）, and photoluminescence（PL） spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi（Φ） scanning curves for ZnO（103） and sapphire（116） substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire, which are ZnO（002）//Al2O3 （006）, ZnO（ 100）//Al2O3 （110） and ZnO（002）//Al2O3 （006）, ZnO（ 110）//Al2O3 （110）. When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO（002）// Al2O3 （006）, ZnO [ 100]//Al2O3 [ 110]. Their photoluminescence（PL） spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.展开更多
ZnO（002） films with different thicknesses ranging from 7 to 300 nm were grown on sapphire（006） substrates via metal-organic chemical vapor deposition （MOCVD）. The two-dimensional（2D） planar layer and the three...ZnO（002） films with different thicknesses ranging from 7 to 300 nm were grown on sapphire（006） substrates via metal-organic chemical vapor deposition （MOCVD）. The two-dimensional（2D） planar layer and the three-dimensional（3D） island layer were studied by using of X-ray diffraction（XRD） rocking curves and atomic force microscopy （AFM）. The room temperature photoluminescence （PL） spectra show a blue shift of the peak positions of the uhraviolet（UV） emission with increasing film thickness. The blue shift is remarkably high（393-380 nm） when an increase in film thickness（7-15 nm） is accompanied by the change of structure from a 2D planar layer to a 3D island layer. The PL spectra at 77 K also indicate that there are different transition mechanisms in the film thickness from a 2D planar layer to a 3D island layer near the 2D layer region.展开更多
ZnO nanoparticles-embedded hydrogenated diamond-like carbon （ZnO-DLC） films have been prepared by electro- chemical deposition in ambient conditions. The morphology, composition, and microstructure of the films have...ZnO nanoparticles-embedded hydrogenated diamond-like carbon （ZnO-DLC） films have been prepared by electro- chemical deposition in ambient conditions. The morphology, composition, and microstructure of the films have been investigated. The results show that the resultant films are hydrogenated diamond-like carbon films embedded with ZnO nanoparticles in wurtzite structure, and the content and size of the ZnO nanoparticles increase with increasing deposition voltage, which are confirmed by X-ray photoelectron spectroscopy （XPS）, Raman, and transmission electron microscope （TEM）. Furthermore, a possible mechanism used to describe the growth process of ZnO-DLC films by electrochemical deposition is also discussed.展开更多
The structure characteristic and electric performance of ZnO film deposited on nucleation side of free-standing diamond substrates under different heating temperatures (Th) of substrate and working pressures (p) were ...The structure characteristic and electric performance of ZnO film deposited on nucleation side of free-standing diamond substrates under different heating temperatures (Th) of substrate and working pressures (p) were studied. The structure of the ZnO films tested by X-ray diffraction shows that ZnO film of high c-axis orientation is deposited on the nucleation side of free-standing diamond substrate which is extremely smooth when Th=250 ℃ and p=0.4 Pa. After annealing at 480 ℃ in N2 atmosphere, the SEM and the AFM analyses demonstrate that the c-axis orientation of ZnO film is obviously enhanced. The resistivity of ZnO films also increases up to 8×105 ■·cm which is observed by I?V test.展开更多
ZnO films with <110> orientation were grown on R-Al 2O 3 substrates by LP-MOCVD, and the growth temperature was optimized. The quality of crystal, surface morphology and optical characteristic of the samples wer...ZnO films with <110> orientation were grown on R-Al 2O 3 substrates by LP-MOCVD, and the growth temperature was optimized. The quality of crystal, surface morphology and optical characteristic of the samples were investigated by XRD, AFM and PL method. The experimental results show that the FWHM of the optimized sample is only 0.50°. Compared with that of the sample grown on C-Al 2O 3 material under the same conditions, the surface morphology of the first sample is denser and smooth, while the PL spectra indicate that the exciton emitting intensity of <110> oriented ZnO film in the ultraviolet range is lower. However, the deep-level emission related to the intrinsic defects disappears in the spectrum. All above indicate that the <110> oriented ZnO film is more suitable for fabrication of the film SAWF with a low loss and a high frequency than for fabrication of the emitting device in ultraviolet range.展开更多
基金National Natural Science Foundation of China (Nos.60577040,60877017)Program for Changjiang Scholars,Innovative Research Team in University of China (No.IRT0739)+1 种基金Innovation Program of Shanghai Municipal Education Commission of China (08YZ04)Shanghai Leading Academic Disciplines of China (S30107)
文摘Highly c-axis-oriented ZnO films were deposited successfully on the nucleation sides of free-standing diamond （FD） films by the direct current （DC） magnetron sputtering method. The effect of the sputtering parameters, such as power, gas pressure and sputtering plasma composition of Ar-to-O2, on the properties of ZnO thin films was investigated in detail. X-ray diffraction （XRD） measurements showed that, at a sputtering power of 200 W, gas pressure of 0.5 Pa and an Ar-to- O2 composition of 1：1, a higher intensity of the （002） diffraction peak and a narrower full width at half maximum （FWHM） were detected which meant high c-axis orientation and high quality of the ZnO films. To improve the quality of the ZnO film, a thin ZnO layer was pre-grown as a homo-buffer layer. XRD measurements showed that this buffer layer had a beneficial effect on the structural and morphological properties of the post-grown ZnO film.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50472009, 10474091 and 50532070)
文摘ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, the deep-level transient spectroscopy （DLTS） and the photoluminescence （PL） spectra of the samples were measured. DLTS shows two deep-level centres of E1 （Ec-0.13±0.02eV） and E2 （Ec-0.43±0.05eV） in sample 1202a, which has a ZnO/p-Si heterostructure. A deep level at Ec-0.13±0.01 eV was also obtained from the I -T characteristics. It was considered to be the same as E1 obtained from DLTS measurement. The emission related to this deep level center was detected by PL spectra. In addition, the energy location and the relative trap density of E1 was varied when the total gas flow rate was changed.
文摘High-quality MgxZn1-xO thin films were grown on sapphire（0001 ） substrates with a ZnO buffer layer of different thicknesses by means of metal-organic chemical vapor deposition. Diethyl zinc, bis-cyclopentadienyl-Mg and oxygen were used as the precursor materials. The crystalline quality, surface morphologies and optical properties of the Mg, Zn1-xO films were investigated by X-ray diffraction, atomic force microscopy and photoluminescence spectrometry. It was shown that the quality of the MgxZn1-xO thin films depends on the thickness of the ZnO buffer layer and an Mg, Zn1-xO thin film with a ZnO buffer layer whose thickness was 20 nm exhibited the best crystal-quality, optical properties and a flat and dense surface.
文摘ZnO films with low resistivity and high transmittance in the visible optical region were deposited on GaAs and glass substrates by MOCVD at atmospheric pressure using diethyl zinc and tetrahydrofuran as precursors.The X ray diffraction results revealed that ZnO epilayer on GaAs showed good crystalline character and exhibited (002) orientation with the c axis perpendicular to the substrate surface.The resistivity of ZnO films in the range from 10 -3 ～10 -2 Ω·cm was found to be dependent upon the initial partial pressure of diethyl zinc and tetrahydrofuran.
基金Supported by the National Natural Science Foundation of China(Nos. 20071013 and 20301007).
文摘ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy（SEM）, and photoluminescence（PL） spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi（Φ） scanning curves for ZnO（103） and sapphire（116） substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire, which are ZnO（002）//Al2O3 （006）, ZnO（ 100）//Al2O3 （110） and ZnO（002）//Al2O3 （006）, ZnO（ 110）//Al2O3 （110）. When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO（002）// Al2O3 （006）, ZnO [ 100]//Al2O3 [ 110]. Their photoluminescence（PL） spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.
基金Supported by the National Natural Science Foundation of China(Nos. 20071013 and 20301007).
文摘ZnO（002） films with different thicknesses ranging from 7 to 300 nm were grown on sapphire（006） substrates via metal-organic chemical vapor deposition （MOCVD）. The two-dimensional（2D） planar layer and the three-dimensional（3D） island layer were studied by using of X-ray diffraction（XRD） rocking curves and atomic force microscopy （AFM）. The room temperature photoluminescence （PL） spectra show a blue shift of the peak positions of the uhraviolet（UV） emission with increasing film thickness. The blue shift is remarkably high（393-380 nm） when an increase in film thickness（7-15 nm） is accompanied by the change of structure from a 2D planar layer to a 3D island layer. The PL spectra at 77 K also indicate that there are different transition mechanisms in the film thickness from a 2D planar layer to a 3D island layer near the 2D layer region.
文摘ZnO nanoparticles-embedded hydrogenated diamond-like carbon （ZnO-DLC） films have been prepared by electro- chemical deposition in ambient conditions. The morphology, composition, and microstructure of the films have been investigated. The results show that the resultant films are hydrogenated diamond-like carbon films embedded with ZnO nanoparticles in wurtzite structure, and the content and size of the ZnO nanoparticles increase with increasing deposition voltage, which are confirmed by X-ray photoelectron spectroscopy （XPS）, Raman, and transmission electron microscope （TEM）. Furthermore, a possible mechanism used to describe the growth process of ZnO-DLC films by electrochemical deposition is also discussed.
基金Project (60577040) supported by the National Natural Science Foundation of China Project (0404) supported by the Shanghai Foundation of Applied Materials Research and Development+1 种基金 Projects(0452nm051, 05nm05046) supported by the Nano-technology Project of Shanghai Project (T0101) supported by the Shanghai Leading Academic Disciplines
文摘The structure characteristic and electric performance of ZnO film deposited on nucleation side of free-standing diamond substrates under different heating temperatures (Th) of substrate and working pressures (p) were studied. The structure of the ZnO films tested by X-ray diffraction shows that ZnO film of high c-axis orientation is deposited on the nucleation side of free-standing diamond substrate which is extremely smooth when Th=250 ℃ and p=0.4 Pa. After annealing at 480 ℃ in N2 atmosphere, the SEM and the AFM analyses demonstrate that the c-axis orientation of ZnO film is obviously enhanced. The resistivity of ZnO films also increases up to 8×105 ■·cm which is observed by I?V test.
基金the National Basic Research Program of China (No.2006CB202602, 2006CB202603)Tianjin Assistant Foundation for the National Basic Research Program of China (07QTPTJC29500 )Doctor Start-up Foundation of Nankai University (No.J02048).
文摘ZnO films with <110> orientation were grown on R-Al 2O 3 substrates by LP-MOCVD, and the growth temperature was optimized. The quality of crystal, surface morphology and optical characteristic of the samples were investigated by XRD, AFM and PL method. The experimental results show that the FWHM of the optimized sample is only 0.50°. Compared with that of the sample grown on C-Al 2O 3 material under the same conditions, the surface morphology of the first sample is denser and smooth, while the PL spectra indicate that the exciton emitting intensity of <110> oriented ZnO film in the ultraviolet range is lower. However, the deep-level emission related to the intrinsic defects disappears in the spectrum. All above indicate that the <110> oriented ZnO film is more suitable for fabrication of the film SAWF with a low loss and a high frequency than for fabrication of the emitting device in ultraviolet range.
