Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field...Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.展开更多
In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor deposition.The diamond films consisting of micro-grains(nano-grai...In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor deposition.The diamond films consisting of micro-grains(nano-grains) were realized with low(high) boron source flow rate during the growth processes.The transition of micro-grains to nano-grains is speculated to be strongly(weekly) related with the boron(nitrogen) flow rate.The grain size and Raman spectral feature vary insignificantly as a function of the nitrogen introduction at a certain boron flow rate.The variation of electron field emission characteristics dependent on nitrogen is different between microcrystalline and nanocrystalline boron doped diamond samples,which are related to the combined phase composition,boron doping level and texture structure.There is an optimum nitrogen proportion to improve the field emission properties of the boron-doped films.展开更多
Nano-diamond particles are co-deposited on Ti substrates with metal(Ti/Ni) nanoparticles(NPs) by the electrophoretic deposition(EPD) method combined with a furnace annealing at 800℃ under N_(2) atmosphere. Modificati...Nano-diamond particles are co-deposited on Ti substrates with metal(Ti/Ni) nanoparticles(NPs) by the electrophoretic deposition(EPD) method combined with a furnace annealing at 800℃ under N_(2) atmosphere. Modifications of structural and electron field emission(EFE) properties of the metal-doped films are investigated with different metal NPs concentrations. Our results show that the surface characteristics and EFE performances of the samples are first enhanced and then reduced with metal NPs concentration increasing. Both the Ti-doped and Ni-doped nano-diamond composite films exhibit optimal EFE and microstructural performances when the doping quantity is 5 mg. Remarkably enhanced EFE properties with a low turn-on field of 1.38 V/μm and a high current density of 1.32 mA/cm^(2) at an applied field of 2.94 V/μm are achieved for Ni-doped nano-diamond films, and are superior to those for Ti-doped ones. The enhancement of the EFE properties for the Ti-doped films results from the formation of the TiC-network after annealing. However, the doping of electron-rich Ni NPs and formation of high conductive graphitic phase are considered to be the factor, which results in marvelous EFE properties for these Ni-doped nano-diamond films.展开更多
In this study, diamond films were synthesized on silicon substrates by microwave plasma enhanced chemical vapor deposition（CVD） over a wide range of experimental parameters. The effects of the microwave power,CH;/H;...In this study, diamond films were synthesized on silicon substrates by microwave plasma enhanced chemical vapor deposition（CVD） over a wide range of experimental parameters. The effects of the microwave power,CH;/H;ratio and gas pressure on the morphology, growth rate, composition, and quality of diamond films were investigated by means of scanning electron microscope（SEM）, X-ray diffraction（XRD）, Raman spectroscopy and X-ray photoelectron spectroscopy（XPS）. A rise of microwave power can lead to an increasing pyrolysis of hydrogen and methane, so that the microcrystalline diamond film could be synthesized at low CH;/H;levels. Gas pressure has similar effect in changing the morphology of diamond films, and high gas pressure also results in dramatically increased grain size. However,diamond film is deteriorated at high CH;/H;ratio due to the abundant graphite content including in the films. Under an extreme condition of high microwave power of 10 kW and high CH;concentration, a hybrid film composed of diamond/graphite was successfully formed in the absence of N;or Ar,which is different from other reports. This composite structure has an excellent measured sheet resistance of 10-100 Ω/Sqr. which allows it to be utilized as field electron emitter. The diamond/graphite hybrid nanostructure displays excellent electron field emission（EFE） properties with a low turn-on field of 2.17 V/μm and β= 3160, therefore it could be a promising alternative in field emission applications.展开更多
The preparation process, structure feature and field electron emission characteristic of diamond films on nanocyrstalline diamond coating by the CVD method were studied. The field electron emission measurements on the...The preparation process, structure feature and field electron emission characteristic of diamond films on nanocyrstalline diamond coating by the CVD method were studied. The field electron emission measurements on the samples showed that the diamond films have lower turn-on voltage and higher field emission current density. A further detailed theory explanation to the results was given.展开更多
Hydrogen-free high sp^3 content amorphous diamond (AD) films are deposited on three different substrates——Au-coated Si (Au/Si), Ti-coated Si (Ti/Si) and Si wafers. Electron field emission properties and fluorescent ...Hydrogen-free high sp^3 content amorphous diamond (AD) films are deposited on three different substrates——Au-coated Si (Au/Si), Ti-coated Si (Ti/Si) and Si wafers. Electron field emission properties and fluorescent displays of the above AD films are studied by using a sample diode structure. The compositional profile of the interfaces of AD/Ti/Si and AD/Si is examined by using secondary ions mass spectroscopy (SIMS). Because of the reaction and interdiffusion between Ti and C, the formation of a thin TiC intermediate layer is possible between AD film and Ti/Si substrate. The field emission properties of AD/Ti/Si are sufficiently improved, especially its uniformity. A field emission density of 0.352 mA/cm^2 is obtained under an electric field of 19.7 V/μm. The value is much more than that of AD/Au/Si and AD/Si under the same electric field.展开更多
We present a scalable, reproducible and economic process for the fabrication of diamond and diamond-graphene hybrid films using paraffin wax as a seeding source for diamond. The films were characterized using Raman sp...We present a scalable, reproducible and economic process for the fabrication of diamond and diamond-graphene hybrid films using paraffin wax as a seeding source for diamond. The films were characterized using Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Raman spectra show the characteristic band of diamond at 1332 cm-1 and the D, G, and 2D bands of graphene at 1360, 1582 and 2709 cm-1, respectively. Electron microscopy confirms the microcrystalline nature of the diamond films with crystal size in the range of 0.5 μm to 1.0 μm, and the hybrid film consists of microcrystalline diamond attached to thin, semi-transparent graphene flakes. The graphene-diamond hybrid films exhibit a turn-on field of about 3.6 V/μm with a prolonged current stability of at least 135 h.展开更多
Details are given of a study of the characteristics of field-induced electron emission from hydrogen-free high sp3 content (>90%) amorphous diamond (a-D) film deposited on heavily doped (ρ<0.01ω·cm) n-typ...Details are given of a study of the characteristics of field-induced electron emission from hydrogen-free high sp3 content (>90%) amorphous diamond (a-D) film deposited on heavily doped (ρ<0.01ω·cm) n-type monocrystalline Si (111) substrate. It is demonstrated that a-D film has excellent electron field emission properties. The emission current can reach 0.9 μA at applied field as low as 1 V/μm, and the emission current density can be about several mA/cm2 under 20 V/μm. The emission current is stable when the beginning current is at 50 μA within 72 h. Uniform fluorescence display of electron emission from the whole face of the a-D film under the electric field of 10–12 V/μm is also observed. The contribution of excellent electron emission property results from the smooth, uniform, amorphous surface and high sp3 content of the a-D film.展开更多
通过改变处理衬底表面的方法,制备出不同的微米金刚石薄膜。具体的方法是利用磁控溅射在陶瓷衬底上面镀上一层厚金属钛,对金属钛层进行不同的表面处理后,放在微波等离子体化学气相沉积腔中制备微米金刚石薄膜。对不同的薄膜用二极管型...通过改变处理衬底表面的方法,制备出不同的微米金刚石薄膜。具体的方法是利用磁控溅射在陶瓷衬底上面镀上一层厚金属钛,对金属钛层进行不同的表面处理后,放在微波等离子体化学气相沉积腔中制备微米金刚石薄膜。对不同的薄膜用二极管型结构测试了它们的场致发射电子的性能,良好的表面处理能达到在电场2.1 V/μm下,9.2 m A/cm^2优秀的发射效果。并对发射机理和场发射特性进行了深入的研究。展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11405114the Natural Science Foundation of Shanxi Province under Grant No 2015021065
文摘Cu ion implantation and subsequent rapid annealing at 500℃ in N2 result in low surface resistivity of 1.611 ohm/sq with high mobility of 290 cm2 V-1S-1 for microcrystalline diamond （MCD） films. Its electrical field emission behavior can be turned on at Eo = 2.6 V/μm, attaining a current density of 19.5μA/cm2 at an applied field of 3.5 V/#m. Field emission scanning electron microscopy combined with Raman and x-ray photoelectron mi- croscopy reveal that the formation of Cu nanoparticles in MCD films can catalytically convert the less conducting disorder/a-C phases into graphitic phases and can provoke the formation of nanographite in the films, forming conduction channels for electron transportation.
基金financially supported by The Program for New Century Excellent Talents in University (NCET)the National Natural Science Foundation of China (NSFC) under Grant No.50772041
文摘In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor deposition.The diamond films consisting of micro-grains(nano-grains) were realized with low(high) boron source flow rate during the growth processes.The transition of micro-grains to nano-grains is speculated to be strongly(weekly) related with the boron(nitrogen) flow rate.The grain size and Raman spectral feature vary insignificantly as a function of the nitrogen introduction at a certain boron flow rate.The variation of electron field emission characteristics dependent on nitrogen is different between microcrystalline and nanocrystalline boron doped diamond samples,which are related to the combined phase composition,boron doping level and texture structure.There is an optimum nitrogen proportion to improve the field emission properties of the boron-doped films.
基金supported by the Science and Technology Major Project of Shanxi Province,China (Grant No. 20181102013)the Fund from the “1331 Project”Engineering Research Center of Shanxi Province,China (Grant No. PT201801)。
文摘Nano-diamond particles are co-deposited on Ti substrates with metal(Ti/Ni) nanoparticles(NPs) by the electrophoretic deposition(EPD) method combined with a furnace annealing at 800℃ under N_(2) atmosphere. Modifications of structural and electron field emission(EFE) properties of the metal-doped films are investigated with different metal NPs concentrations. Our results show that the surface characteristics and EFE performances of the samples are first enhanced and then reduced with metal NPs concentration increasing. Both the Ti-doped and Ni-doped nano-diamond composite films exhibit optimal EFE and microstructural performances when the doping quantity is 5 mg. Remarkably enhanced EFE properties with a low turn-on field of 1.38 V/μm and a high current density of 1.32 mA/cm^(2) at an applied field of 2.94 V/μm are achieved for Ni-doped nano-diamond films, and are superior to those for Ti-doped ones. The enhancement of the EFE properties for the Ti-doped films results from the formation of the TiC-network after annealing. However, the doping of electron-rich Ni NPs and formation of high conductive graphitic phase are considered to be the factor, which results in marvelous EFE properties for these Ni-doped nano-diamond films.
基金financial support from the Project supported by the National Natural Science Foundation of China(Grant No.51202257)Shenyang Double-Hundreds Project(Z17-7-027,Z18-0-025)
文摘In this study, diamond films were synthesized on silicon substrates by microwave plasma enhanced chemical vapor deposition（CVD） over a wide range of experimental parameters. The effects of the microwave power,CH;/H;ratio and gas pressure on the morphology, growth rate, composition, and quality of diamond films were investigated by means of scanning electron microscope（SEM）, X-ray diffraction（XRD）, Raman spectroscopy and X-ray photoelectron spectroscopy（XPS）. A rise of microwave power can lead to an increasing pyrolysis of hydrogen and methane, so that the microcrystalline diamond film could be synthesized at low CH;/H;levels. Gas pressure has similar effect in changing the morphology of diamond films, and high gas pressure also results in dramatically increased grain size. However,diamond film is deteriorated at high CH;/H;ratio due to the abundant graphite content including in the films. Under an extreme condition of high microwave power of 10 kW and high CH;concentration, a hybrid film composed of diamond/graphite was successfully formed in the absence of N;or Ar,which is different from other reports. This composite structure has an excellent measured sheet resistance of 10-100 Ω/Sqr. which allows it to be utilized as field electron emitter. The diamond/graphite hybrid nanostructure displays excellent electron field emission（EFE） properties with a low turn-on field of 2.17 V/μm and β= 3160, therefore it could be a promising alternative in field emission applications.
文摘The preparation process, structure feature and field electron emission characteristic of diamond films on nanocyrstalline diamond coating by the CVD method were studied. The field electron emission measurements on the samples showed that the diamond films have lower turn-on voltage and higher field emission current density. A further detailed theory explanation to the results was given.
基金Project supported by the National High-Tech Program of China.
文摘Hydrogen-free high sp^3 content amorphous diamond (AD) films are deposited on three different substrates——Au-coated Si (Au/Si), Ti-coated Si (Ti/Si) and Si wafers. Electron field emission properties and fluorescent displays of the above AD films are studied by using a sample diode structure. The compositional profile of the interfaces of AD/Ti/Si and AD/Si is examined by using secondary ions mass spectroscopy (SIMS). Because of the reaction and interdiffusion between Ti and C, the formation of a thin TiC intermediate layer is possible between AD film and Ti/Si substrate. The field emission properties of AD/Ti/Si are sufficiently improved, especially its uniformity. A field emission density of 0.352 mA/cm^2 is obtained under an electric field of 19.7 V/μm. The value is much more than that of AD/Au/Si and AD/Si under the same electric field.
文摘We present a scalable, reproducible and economic process for the fabrication of diamond and diamond-graphene hybrid films using paraffin wax as a seeding source for diamond. The films were characterized using Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). Raman spectra show the characteristic band of diamond at 1332 cm-1 and the D, G, and 2D bands of graphene at 1360, 1582 and 2709 cm-1, respectively. Electron microscopy confirms the microcrystalline nature of the diamond films with crystal size in the range of 0.5 μm to 1.0 μm, and the hybrid film consists of microcrystalline diamond attached to thin, semi-transparent graphene flakes. The graphene-diamond hybrid films exhibit a turn-on field of about 3.6 V/μm with a prolonged current stability of at least 135 h.
基金Project supported by the National High-Tech Program of China
文摘Details are given of a study of the characteristics of field-induced electron emission from hydrogen-free high sp3 content (>90%) amorphous diamond (a-D) film deposited on heavily doped (ρ<0.01ω·cm) n-type monocrystalline Si (111) substrate. It is demonstrated that a-D film has excellent electron field emission properties. The emission current can reach 0.9 μA at applied field as low as 1 V/μm, and the emission current density can be about several mA/cm2 under 20 V/μm. The emission current is stable when the beginning current is at 50 μA within 72 h. Uniform fluorescence display of electron emission from the whole face of the a-D film under the electric field of 10–12 V/μm is also observed. The contribution of excellent electron emission property results from the smooth, uniform, amorphous surface and high sp3 content of the a-D film.
文摘通过改变处理衬底表面的方法,制备出不同的微米金刚石薄膜。具体的方法是利用磁控溅射在陶瓷衬底上面镀上一层厚金属钛,对金属钛层进行不同的表面处理后,放在微波等离子体化学气相沉积腔中制备微米金刚石薄膜。对不同的薄膜用二极管型结构测试了它们的场致发射电子的性能,良好的表面处理能达到在电场2.1 V/μm下,9.2 m A/cm^2优秀的发射效果。并对发射机理和场发射特性进行了深入的研究。
