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1.
Enhancing the thermal conductivity of polymer-assisted deposited Al2O3 film by nitrogen doping
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<正>Polymer-assisted deposition technique has been used to deposit Al2O3 and N-doped Al2O3(AlON) thin films on Si(100) substrates.The chemical compositions,crystallinity,and thermal conductivity of the as-grown films have been characterized by X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),and 3-omega method,respectively. Amorphous and polycrystalline Al2O3 and AlON thin films have been formed at 700℃and 1000℃.The thermal conductivity results indicated that the effect of nitrogen doping on the thermal conductivity is determined by the competition of the increase of Al-N bonding and the suppression of crystallinity.A 67%enhancement in thermal conductivity has been achieved for the samples grown at 700℃,demonstrating that the nitrogen doping is an effective way to improve the thermal performance of polymer-assisted-deposited Al2O3 thin films at a relatively low growth temperature. 相似文献
2.
《Current Applied Physics》2014,14(12):1845-1848
Nitrogen-doped amorphous carbon thin films (a-CNx) were prepared on silicon substrate by pulsed laser deposition process using methane (CH4) and nitrogen (N2) as source gas. The electrical properties of a-CNx films changes with nitrogen concentration in the film structure. The intensity ratio of the D and G peak (ID/IG) increases with higher nitrogen concentration, which means that sp2-clusters were formed in these films and is responsible for the enhancement of conductivity of the a-CNx films. We observed that the amorphous carbon (a-C) films becoming more graphitic in nature yielding higher conductivity/lower resistivity with increase of nitrogen concentration. Electron field emission result shows that the emission current density enhances with nitrogen doping that indicates the useful in electron field emission devices application. 相似文献
3.
In situ photoemission (UPS and XPS) measurements have been performed for amorphous GeTe films. The photoemission spectra exhibit a drastic change upon thermal annealing and/or the crystallization of the film. It has been found that an amorphous GeTe film deposited onto a room temperature substrate has a 4-2 coordinated local structure, while a highly disordered amorphous GeTe film evaporated onto a cooled (77 K) substrate is largely 3-3 coordinated, and relaxes into the 4-2 coordinated structure upon thermal annealing within amorphous phase. 相似文献
4.
The effects of nitrogen doping on the chemical bonding state, microstructure, electrical property and thermal stability of Ge15Sb85 film were investigated in detail. The doped N atoms tend to bond with Ge to form Ge3N4, as proved by X-ray photoelectron spectroscopy analyses. X-ray diffraction patterns showed that both undoped and N-doped Ge15Sb85 films crystallize into a hexagonal phase very similar to Sb. The thickness reduction upon crystallization for undoped and N-doped Ge15Sb85 films is less than 5%. The crystalline resistivity, crystallization temperature, and thermal stability of amorphous state all increase after nitrogen doping, while the grain size decreases. By adding 7.0 at.% N into the Ge15Sb85 film, the crystalline resistivity increases twelve times and the crystallization temperature increases about 50 °C. The maximum temperature for 10-year retention of amorphous Ge15Sb85 film is estimated to be 147 °C and that of N-doped films is even higher, which will promise better data retention of phase-change random access memory especially in the high-temperature application. 相似文献
5.
Jie Feng Yin Zhang Bingchu Cai Bomy Chen 《Applied Physics A: Materials Science & Processing》2009,97(2):507-511
Undoped and N-doped Si10.5Sb89.5 films were deposited by magnetron sputtering. The X-ray diffraction spectra indicated that all of the films crystallized
into crystalline Sb with a rhombohedral structure after annealing at 280°C for 3 min. X-ray photoelectron spectroscopy analysis
indicated that the incorporated nitrogen combined with Si to form silicon nitride in the SiSb films. The changes in electrical
resistance and thermal stability of the undoped and N-doped Si10.5Sb89.5 films were investigated. The crystallization temperature increased from ∼225°C to ∼250°C when 13 at.% nitrogen was added
into the Si10.5Sb89.5 film and increased further with increasing nitrogen content. The thermal stability of the amorphous film was enhanced by
nitrogen doping. The maximum temperature for 10-year retention of amorphous state of a pure Si10.5Sb89.5 film is ∼140°C and the temperature of N-doped Si10.5Sb89.5 films is even higher, which may be helpful to improve the data retention and performance of phase-change memory in high temperature
applications. 相似文献
6.
The temperature dependence of the dc conductivity and thermoelectric power was determined for five different amorphous chalcogenide Se–Ge–Te films, with Ge?=?3.0–22?at.%, Se?=?0–97?at.% and Te?=?0–97?at.%. The films were prepared by thermal evaporation of GeSe4, GeTe4 and GeSe2Te2 quenched bulk materials. Values of the activation energy calculated from the temperature dependence of both electrical conductivity and thermoelectric power showed a decrease with increasing Ge content in the Se–Ge films as well as with replacement of Te for Se in the Se–Ge–Te films. The results showed an Anderson transition, with the conductivity showing insulating behaviour on the Ge–Se side to metallic behaviour at the binary composition Ge–Te. The radius of localization was obtained for the different compositions investigated. The wave function associated with the charge carriers at the composition Ge3.3Te96.7 is non-localized. A minimum metallic conductivity of 237?±?5?(Ω?cm)?1 was found. 相似文献
7.
Electrical and optical studies have been carried out on aluminium-modified Ge2Sb2Te5 thin films to check its applicability as an active material in optical and electrical memory storage devices. Five polycrystalline bulk samples were prepared with compositions: Alx(Ge2Sb2Te5)1?x; x = 0, 0.08, 0.14, 0.21, 0.25. Amorphous thin films were deposited from the polycrystalline bulk by thermal evaporation. Temperature-dependent resistance shows the increase in crystallization temperature of Ge–Sb–Te films on aluminium addition. Activation energy for conduction, conductivity, optical band gap, coefficient of refraction and extinction coefficient are studied with respect to Al content in both amorphous and crystalline phases of Ge–Sb–Te alloy films. 相似文献
8.
Anek Charoenphakdee Ken Kurosaki Hiroaki Muta Masayoshi Uno Shinsuke Yamanaka 《固体物理学:研究快报》2008,2(2):65-67
High‐density polycrystalline samples (above 98% of the theoretical density) of Ag8GeTe6 were prepared by solid‐state reactions of Ag2Te, GeTe, and Te, followed by hot‐pressing. The thermoelectric properties were measured at temperatures ranging from room temperature to around 700 K. The thermal conductivity values were extremely low (0.25 Wm–1 K–1 at room temperature), and consequently Ag8GeTe6 exhibited a relatively high thermoelectric figure of merit, ZT = 0.48 at 703 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
以B2H6为掺杂剂,采用射频等离子体增强化学气相沉积技术在玻璃衬底上制备p型氢化微晶硅薄膜.研究了衬底温度和硼烷掺杂比对薄膜的微结构和暗电导率的影响.结果表明:在较高的衬底温度下很低的硼烷掺杂比即可导致薄膜非晶化;在实验范围内,随着衬底温度升高薄膜的晶化率单调下降,暗电导率先缓慢增加然后迅速下降,变化趋势与硼烷掺杂比的影响极为相似.最后着重讨论了p型氢化微晶硅薄膜的生长机理.
关键词:
p型氢化微晶硅薄膜
衬底温度
晶化率
电导率 相似文献
10.
M. Safonchik K. Traito S. Tuominen P. Paturi H. Huhtinen R. Laiho 《Physica C: Superconductivity and its Applications》2009,469(22):1983-1986
Hall effect and flux pinning in YBa2Cu3O6+x (YBCO) thin films doped with BaZrO3 (BZO) nanoparticles is investigated. The results show that sign reversal of the Hall coefficient from positive hole-like to negative electron-like occurs in vortex-liquid regime of undoped and BZO-doped YBCO films. With increasing BZO concentration the amplitude of the negative Hall effect is suppressed while the temperature position of the anomalous Hall effect does not depend significantly on doping level. In addition, it is shown that Hall conductivity increases non-monotonically with increasing BZO doping. These results support a model where BZO at low doping concentration induces point pinning centres turning to strong columnar pinning defects in films doped with 4% BZO. 相似文献
11.
V. N. Bogomolov N. F. Kartenko D. A. Kurdyukov L. S. Parfen’eva I. A. Smirnov N. V. Sharenkova H. Misiorek A. Jezowski 《Physics of the Solid State》2003,45(5):957-960
The effective thermal conductivity κeff of seven opal + epoxy resin nanocomposite samples with 100% filling of first-order pores by epoxy resin was measured in the 100-to 300-K temperature interval. In the nanocomposite studied, the thermal conductivity of the matrix (amorphous SiO2 spheres) is larger than that of the filler material (epoxy resin). κeff(T) of the opal + epoxy resin nanocomposite at intermediate temperatures (100–300 K) is shown to behave similar to pure opal. An explanation of the observed effect is proposed. 相似文献
12.
The large variation in the characteristic temperature (Tt) obtained for undoped hydrogenated amorphous silicon films from space charge limited currents is explained by dopant contamination from adjacent n+-type contact layers. This uncontrolled doping effect can make films sensitive to photoinduced conductivity changes. Their conduction characteristics, and hence Tt, will then depend on previous heating and illumination history. 相似文献
13.
G. Murtaza Rai M.A. IqbalI.G. Will Z.C. Huang 《Journal of magnetism and magnetic materials》2011,323(24):3239-3245
The samarium doping zinc oxide (Zn1-xSmxO) with (x=0.0, 0.04, 0.05 and 0.17) polycrystalline thin films have been deposited on n-Si(1 0 0) substrate using thermal evaporation technique. Ceramic targets for deposition were prepared by the standard solid-state reaction method and sintered in nitrogen atmospheres. X-ray diffraction and scanning electron microscopy analyses show that the bulk and films features reveal wurtzite crystal structure with a preferential (1 0 1) crystallographic orientation and grows as hexagonal shape grains. According to the results of the Hall effect measurements, all the films show p-type conductivity, possibly a result of nitrogen incorporation into the Sm-doped ZnO samples. Magnetic measurements show that ferromagnetic behavior depends on the Sm3+ concentration. For a film with lower Sm2O3 contents (x=0.04), a phenomenon of paramagnetism has been observed. While, with further increase of Sm3+ contents (x=0.05) the ferromagnetic behavior has been observed at room temperature. However, at higher doping content of Sm3+, the ferromagnetic behavior was suppressed. The decrease of ferromagnetism with increasing doping concentration demonstrates that ferromagnetism observed at room temperature is an intrinsic property of Zn1-xSmxO films. 相似文献
14.
Solid polymer electrolyte films based on Poly(ethylene oxide) (PEO) complexed with lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC) and amorphous carbon nanotube (αCNTs) were prepared by the solution cast technique. The conductivity increases from 10?10 to 10?5 Scm?1 upon the addition of salt. The incorporation of EC and αCNTs to the salted polymer enhances the conductivity significantly to 10?4 and 10?3 Scm?1. The complexation of doping materials with polymer were confirmed by X-ray diffraction and infrared studies. Optical properties like direct band gap and indirect band gap were investigated for pure and doped polymer films in the wavelength range 200–400 nm. It was found that the energy gaps and band edge values shifted to lower energies on doping. 相似文献
15.
The study of plasma-deposited hydrogenated amorphous silicon films prepared in various deposition systems and under the use of different gases (SiH4, SiD4, Si2H4) shows a unique correlation between the photoconductivity and the dark conductivity of undoped and lightly doped films grown under optimized conditions. Deviations from his relation occur at high doping levels, in particular for boron doping, as well as upon annealing. They are attributed to an increased density of gap states due to hydrogen depletion. 相似文献
16.
L. S. Gorbatenko O. A. Novodvorsky V. Ya. Panchenko O. D. Khramova Ye. A. Cherebilo A. A. Lotin C. Wenzel N. Trumpaicka J. W. Bartha 《Laser Physics》2009,19(5):1152-1158
The thin films of zinc oxide have been produced by the pulse laser deposition method at various levels of gallium and nitrogen doping. To obtain the n-type films we used gallium doping with concentration of gallium from zero up to 5 at %. The dependence of photoluminescence of the epitaxial ZnO:Ga films on the concentration of gallium doping has been studied. An optimum range of the n-type ZnO films doping with gallium has been determined to obtain highly effective films from the viewpoint of realizing p-n transitions. This range, on the one hand, defines the maximal PL amplitude and, on the other hand, specifies the minimal specific resistance that corresponds to an interval of 0.125–1.000 at % Ga. To produce the p-type ZnO:(Ga, N) films, the ZnO targets with the content of GaN from zero up to 2 at % were used. N2O was used as a buffer gas. A difference is observed in the positions of the peaks of the emission lines of the photoluminescence spectra for the ZnO films, doped with gallium (Ga) and co-doped with gallium and nitrogen (N). 相似文献
17.
Murat Durandurdu 《哲学杂志》2016,96(11):1110-1121
We report the electronic structure and topology of a heavily Si-doped amorphous aluminium nitride (Al37.5Si12.5N50) using ab initio simulations. The amorphous Al37.5Si12.5N50 system is found to be structurally similar to pure amorphous aluminium nitride. It has an average coordination number of about 3.9 and exhibits a small amount of Si–Si homopolar bonds. The formation of Si–Al bonds is not very favourable. Electronic structure calculations reveal that the Si doping has a negligible effect on the band gap width but causes delocalization of the valence band tail states and a shift of the Fermi level towards the conduction band. Thus, amorphous Al37.5Si12.5N50 alloys show n-type conductivity. 相似文献
18.
Impact of nitrogen doping on growth and hydrogen impurity incorporation of thick nanocrystalline diamond films
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A much larger amount of bonded hydrogen was found in thick nanocrystalline diamond(NCD) films produced by only adding 0.24% N2 into 4% CH4 /H2 plasma,as compared to the high quality transparent microcrystalline diamond(MCD) films,grown using the same growth parameters except for nitrogen.These experimental results clearly evidence that defect formation and impurity incorporation(for example,N and H) impeding diamond grain growth is the main formation mechanism of NCD upon nitrogen doping and strongly support the model proposed in the literature that nitrogen competes with CH x(x=1,2,3) growth species for adsorption sites. 相似文献
19.
The thermal conductivity of quenched condensed polycrystalline and amorphous Pb and Pb0.9Cu0.1 films has been measured between 0.5 and 11 K, i.e. in the superconducting (T7 K) and in the normal state (T7 K). Whereas, in agreement with previous results, phonon heat transport is very small for crystalline films, a considerable portion of heat is carried by phonons in amorphous films, owing to the absence of extended lattice defects. Phonon scattering in these latter films is analyzed in terms of scattering from conduction electrons aboveT
c, whereas well belowT
c it is very likely due to low energy excitations inherent in the amorphous structure.Work performed within the research program of the Sonderforschungsbereich 125 — Aachen/Jülich/Köln 相似文献
20.
Aluminium-doped (Al = 0–5?wt.%) SnO2 thin films with low-electrical resistivity and high optical transparency have been successfully synthesized by pulsed laser deposition technique at 500 °C. Structural, optical and electrical properties of the as-deposited and post-annealed thin films were investigated. X-ray diffraction patterns suggest that the films transform from crystalline to amorphous state with increasing aluminium content. The root mean square (Rq) surface roughness parameter, determined by atomic force microscopy decreases upon annealing of the as-deposited film. While resistivity of the film is the lowest (9.49 × 10?4 Ω-cm) at a critical doping level of 1?wt.% Al, optical transparency is the highest (nearly 90%) in the as-deposited condition. Temperature dependence of the electrical resistivity suggests that the Mott’s variable range hopping process is the dominant carrier transport mechanism in the lower temperature range (40–135 K) for all the films whereas, thermally activated band conduction mechanism seems to account for conduction in the higher temperature region (200–300 K). 相似文献