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用热丝辅助微波电子回旋共振化学气相沉积方法制备出高晶化体积分数的氢化微晶硅(μc-Si:H)薄膜.拉曼散射和X射线衍射技术对样品的微观结构测量分析表明,当反应气体中SiH4浓度在3.6%—50%之间大范围变化时,μc-Si:H薄膜均具有高的晶化体积分数.进一步的分析表明,在SiH4浓度较大时制备的薄膜,其结构以非晶-微晶的过渡相为主.薄膜易于晶化或生长为过渡相的主要原因是微波电子回旋共振使SiH4气体高度分解,等离子体高度电离.
关键词:
微波电子回旋共振化学气相沉积
氢化微晶硅薄膜
拉曼散射
X射线衍射 相似文献
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利用等离子体增强化学气相沉积技术研制出了优质稳定的氢化非晶-纳米晶两相结构硅薄膜.薄膜的光电导率相对于器件质量的非晶硅有两个数量级的提高;光敏性也较好,光、暗电导比可以达到104,此外薄膜的光电导谱具有更宽的长波光谱响应.更为重要 的是薄膜的光致退化效应远小于典型的非晶硅薄膜,在光强为50mW/cm2的卤钨灯光 照24h后,光电导的衰退小于10%.这种薄膜优良的光电性能源于薄膜中的非晶母体的存在使其在 光学跃迁中的动量选择定则发生松弛,因而具有大的光学吸收系数和
关键词:
非晶硅
微结构
光致变化 相似文献
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在苯(C6H6)和四氟化碳(CF4)混合气体中,用微波电子回旋共振等离子体化学气相沉积技术(ECRCVD)在不同功率下制备了氟化非晶碳膜(aC:F),为了检测膜的热稳定性对其进行了真空退火处理,测量了退火前后膜厚的变化率,并用傅里叶变换红外吸收光谱(FTIR)研究了其结构的变化.结果表明,膜厚变化率与沉积功率有关;400℃退火后低功率下沉积的膜的结构变化显著,高功率下沉积的膜则呈现了较好的热稳定性.
关键词:
ECR-CVD
aC:F薄膜
真空退火 相似文献
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对以SiH4/H2及SiCl4/H2为源气体、采用 等离子体增强化学气相沉积技术制备的非晶硅薄膜和多晶硅薄膜进行了光照稳定性的研究.实验表明,制备的多晶硅薄膜并没有出现 非晶硅中的光致衰减现象,其光电导、暗电导在光照过程中没有下降反而有所上升且电导率 变化快慢受氢稀释度的制约.多晶硅薄膜的光照稳定性可能来源于高的晶化度及Cl元素的存在.
关键词:
多晶硅薄膜
稳恒光电导效应
晶界
光致衰退效应 相似文献
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采用等离子体化学气相沉积技术制备氢化非晶硅薄膜,经过不同温度下的热退火处理,使薄膜由非晶结构向晶化结构转变,得到含有纳米晶粒的晶化硅薄膜.在晶化过程中,采用Raman技术对样品的结构进行表征.通过变温电导率的测试,对薄膜的电学输运性质进行了分析.研究结果表明:退火温度为700 ℃时,样品中开始有纳米晶形成,随着退火温度的增加,样品的晶化比增大,在1000 ℃时,薄膜的晶化比达到90%以上.在700 ℃退火时,薄膜中晶化成分较低,载流子的传输特性主要受到与硅悬挂键有关的缺陷态影响,表现为带尾定域态的跳跃电导
关键词:
氢化非晶硅
退火
纳米硅
电输运 相似文献
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采用等离子体增强化学气相沉积法生长的单层本征氢化非晶硅薄膜对单晶硅片进行钝化,结果表明增加氢稀释比有利于减少薄膜中的缺陷,增强钝化效果,过量的氢稀释比会导致非晶硅在硅片表面的外延晶化生长,降低钝化效果。退火导致非晶硅晶化程度增加,降低了钝化效果,同时退火提升了薄膜的质量,改变了H键合方式,增强了钝化效果。因此,单层氢化非晶硅只有在合适的氢稀释比和退火温度才可以获得最佳钝化效果。为了提高非晶硅薄膜对硅片的钝化效果,采用具有高低氢稀释比的叠层本征非晶硅薄膜对硅片进行钝化。因此将高氢稀释比沉积的非晶硅薄膜叠层生长于低氢稀释比的薄膜之上,避免非晶硅在硅片表面的外延生长。在退火过程中,高氢稀释比薄膜中的氢扩散到低氢稀释比薄膜中,有效地钝化了非晶硅中和单晶硅表面的悬挂键,改善了非晶硅/硅片的界面质量,叠层钝化后硅片的少子寿命为7.36 ms,隐含开路电压为732 mV。 相似文献
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采用微波电子回旋共振等离子体化学气相沉积(MWPECRCVD)方法,使用不同的源气体(CHF3CH4,CHF3C2H2,CHF3C6H6)体系制备了aC∶F∶H薄膜.由于CH4,C2H2,C6H6气体在等离子体中的分解反应不同导致了薄膜的沉积速率和结构上的差异.红外吸收谱的结果表明,用C6H6CHF3作为源气体沉积的薄膜中几乎不含H,而用C2H2CHF3所沉积的薄膜中的含氟量最高,其相应的CF振动峰位向高频方向偏移.薄膜的真空退火结果表明,aC∶F∶H薄膜的热稳定性除了取决于薄膜的CC键浓度外,还与CC键
关键词:
氟化非晶碳膜
电子回旋共振化学气相沉积
红外吸收光谱 相似文献
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微波电子回旋共振—化学气相沉只SiNx薄膜的光学性能研究 总被引:1,自引:0,他引:1
研究了微波电子回旋共振-化学气相沉积SiNx薄膜的光学性能,这种SiNx薄膜具有透光谱宽,透光率高的特点,总结了透光谱,折射率,光隙能随微波功率,基片温度的变化关系。 相似文献
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Observational constraints on the accelerating universe in the framework of a 5D bounce cosmological model 下载免费PDF全文
In the framework of a five-dimensional (5D) bounce cosmological model, a useful function f(z) is obtained by giving a concrete expression of deceleration parameter q(z)=q1+{q2}/{1+ln (1+ z)}. Then using the obtained Hubble parameter H(z) according to the function f(z), we constrain the accelerating universe from
recent cosmic observations: the 192 ESSENCE SNe Ia and the 9 observational H(z) data. The best fitting values of transition redshift zT and current deceleration parameter q0 are given as zT= 0.65-0.120.25 and q0 = - 0.76-0.15+0.15 (1σ). Furthermore, in the 5D bounce model it can be seen that the evolution of equation of state (EOS) for dark energy wde can cross over -1 at about z=0.23 and the current
value w0de= - 1.15<- 1. On the other hand, by giving a concrete expression of model-independent EOS of dark energy wde, in the 5D bounce model we obtain the best fitting values zT= 0.660.08+0.11 and q0 = - 0.690.10+0.10 (1σ) from the recently observed data: the 192 ESSENCE SNe Ia, the observational H(z) data, the 3-year Wilkinson Microwave Anisotropy Probe (WMAP), the Sloan Digital Sky Survey (SDSS) baryon acoustic peak and the x-ray gas mass fraction in clusters. 相似文献
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The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length
method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were
fabricated, and irradiated with 1~MeV electrons up to a dose of
3.43× 1014~e/cm-2. After radiation, the forward
currents of the SBDs at 2~V decreased by about 50%, and the
reverse currents at -200~V increased by less than 30%. Schottky
barrier height (φ B ) of the Ni/4H-SiC SBD increased
from 1.20~eV to 1.21~eV under 0~V irradiation bias, and decreased
from 1.25~eV to 1.19~eV under -30~V irradiation bias. The
degradation of φ B could be explained by the variation
of interface states of Schottky contacts. The on-state resistance
(Rs) and the reverse current increased with the dose, which
can be ascribed to the radiation defects in bulk material. The
specific contact resistance (\rhoc) of the Ni/SiC Ohmic
contact increased from 5.11× 105~Ωega.cm2 to 2.97× 10-4~Ωega.cm2. 相似文献
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This paper calculates the transition wavelengths and probabilities
of the two-electron and one-photon (TEOP) transition from the
$(3{\rm s}^{-1}_{1/2}4{\rm d}_{j})_{J=1,2}$ to $(3{\rm
p}^{-1}_{3/2}4{\rm s}_{1/2})_{J=1}$ and the $(3{\rm
p}^{-1}_{1/2}4{\rm s}_{1/2})_{J=1}$ to $(3{\rm d}^{-1}_{j}4{\rm
d}_{j'})_{J=1,2}$ for highly charged Ni-like ions with atomic number
$Z$ in the range $47\leq Z\leq92$. In the calculations, the
multi-configuration Dirac--Fock method and corresponding program
packages GRASP92 and REOS99 were used, and the relativistic effects,
correlation effects and relaxation effects were considered
systematically. It is found that the TEOP transitions are very
sensitive to the correlation of electrons, and the probabilities
will be enhanced sharply in some special $Z$ regions along the
isoelectronic sequence. The present TEOP transition wavelengths are
compared with the available data from some previous publications,
good agreement is obtained. 相似文献
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We report the constraints of $H_0$ obtained from Wilkinson Microwave Anisotropy Probe (WMAP) 9-year data combined with the latest baryonic acoustic oscillations (BAO) measurements. We use the BAO measurements from 6dF Galaxy Survey (6dFGS), the SDSS DR7 main galaxies sample (MGS), the BOSS DR12 galaxies, and the eBOSS DR14 quasars. Adding the recent BAO measurements to the cosmic microwave background (CMB) data from WMAP, we constrain cosmological parameters $\Omega_m=0.298\pm0.005$, $H_0=68.36^{+0.53}_{-0.52} {\rm km}\cdot {\rm s}^{-1}\cdot {\rm Mpc}^{-1}$, $\sigma_8=0.8170^{+0.0159}_{-0.0175}$ in a spatially flat $\Lambda$ cold dark matter ($\Lambda$CDM) model, and $\Omega_m=0.302\pm0.008$, $H_0=67.63\pm1.30 {\rm km}\cdot{\rm s}^{-1}\cdot {\rm Mpc}^{-1}$, $\sigma_8=0.7988^{+0.0345}_{-0.0338}$ in a spatially flat $w$CDM model, respectively. Our measured $H_0$ results prefer a value lower than 70 ${\rm km}\cdot {\rm s}^{-1}\cdot{\rm Mpc}^{-1}$, consistent with the recent data on CMB constraints from Planck (2018), but in $3.1$ and $3.5\sigma$ tension with local measurements of SH0ES (2018) in $\Lambda$CDM and $w$CDM framework, respectively. Our results indicate that there is a systematic tension on the Hubble constant between SH0ES and the combination of CMB and BAO datasets. 相似文献
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This paper investigates the infrared absorption spectra of oxygen-related complexes in silicon crystals irradiated with
electron (1.5~MeV) at 360~K. Two groups of samples with low [Oi]=6.9× 1017~cm-3 and high [ Oi]=1.06× 1018~cm-3 were used. We found that the
concentration of the VO pairs have different behaviour to the
annealing temperature in different concentration of oxygen specimen,
it is hardly changed in the higher concentration of oxygen specimen. It
was also found that the concentration of VO2 in lower concentration
of oxygen specimen gets to maximum at 450~℃ and then
dissapears at 500~℃, accompanied with the appearing of
VO3. For both kinds of specimens, the concentration of VO3
reachs to maximum at 550~℃ and does not disappear
completely at 600~℃. 相似文献
16.
本文考虑带有黑洞视界和宇宙视界的Kiselev时空.研究以黑洞视界和宇宙视界为边界的系统的热力学性质.统一地给出了两个系统的热力学第一定律;在黑洞视界半径远小于宇宙视界半径的情况下,近似地计算了通过宇宙视界和黑洞视界的热能.然后,探讨Kiselev时空的物质吸积特性.在吸积能量密度正比于背景能量密度的条件下给出黑洞的吸积率,讨论了黑洞吸积率与暗能量态方程参数的关系. 相似文献
17.
Electron tunnelling phase time and dwell time through an associated delta potential barrier 下载免费PDF全文
The electron tunnelling phase time τP and dwell time τD through an associated delta potential barrier U(x) = ξδ(x) are calculated and both are in the order of 10^-17~10^-16s. The results show that the dependence of the phase time on the delta barrier parameter ξ can be described by the characteristic length lc = h^2/meξ and the characteristic energy Ec=meξ^2/h^2 of the delta barrier, where me is the electron mass, lc and Ec are assumed to be the effective width and height of the delta barrier with lcEc=ξ, respectively. It is found that TD reaches its maximum and τD = τp as the energy of the tunnelling electron is equal to Ec/2, i.e. as lc =λDB, λDB is de Broglie wave length of the electron. 相似文献
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We search for isotropic stochastic gravitational-wave background (SGWB) in the International Pulsar Timing Array second data release. By modeling the SGWB as a power-law, we find very strong Bayesian evidence for a common-spectrum process, and further this process has scalar transverse (ST) correlations allowed in general metric theory of gravity as the Bayes factor in favor of the ST-correlated process versus the spatially uncorrelated common-spectrum process is 30 ± 2. The median and the 90% equal-tail amplitudes of ST mode are ${{ \mathcal A }}_{\mathrm{ST}}={1.29}_{-0.44}^{+0.51}\times {10}^{-15}$, or equivalently the energy density parameter per logarithm frequency is ${{\rm{\Omega }}}_{\mathrm{GW}}^{\mathrm{ST}}={2.31}_{-1.30}^{+2.19}\times {10}^{-9}$, at frequency of 1 year−1. However, we do not find any statistically significant evidence for the tensor transverse (TT) mode and then place the 95% upper limits as ${{ \mathcal A }}_{\mathrm{TT}}\lt 3.95\times {10}^{-15}$, or equivalently ${{\rm{\Omega }}}_{\mathrm{GW}}^{\mathrm{TT}}\lt 2.16\times {10}^{-9}$, at frequency of 1 year−1. 相似文献
19.
Coherent interaction and action-counteraction theory in small polaron systems,and ground state properties 下载免费PDF全文
Zhi-Hua Luo 《中国物理 B》2022,31(11):117104-117104
Based on the coherent interaction and action-counteraction principles, we investigate the ground state properties for small polaron systems, the coherent-squeezed fluctuation correction, and the anomalous lattice quantum fluctuation, with the new variational generator containing correlated squeezed-coherent coupling and quantum entanglement. Noting that $-2t $ is the T.B.A. energy, for the coherent interaction effect, we find the ground-state energy $E_0$ to be $-2.428t$, in which the coherent squeezed fluctuation correction $-A_0 t$ is $-0.463t $ (where $ t $ is the hopping integral, $\omega $ is the phonon frequency), with the electron-one-phonon coupling constant $g=$1 and the electron-two-phonon coupling constant $g_{1}=-0.1$. However, as a result of the action-counteraction effect, $\tilde{{E}}_{0} $ is $-2.788t$, but $-\tilde{{A}}_{0} t$ is $-0.735t$. As to the polaron binding energy $(E_{\rm P} )$, for the coherent interaction effect, $E_{\rm P} $ is $-1.38\omega $, but for the action-counteraction effect, $\tilde{{E}}_{\rm P}$ is $-1.88\omega $. In particular, the electron-two-phonon interaction noticeably enlarges the coherent interaction and the coherent squeezed quantum fluctuation correction. By intervening with the quantum entanglement, the evolutions of the squeezed coherent state and the lattice quantum fluctuation begin to take control. At that time, we encounter a new quantum phase coherence phenomenon — the collapse and revival of inversion repeatedly for the coherent state in the entangled evolution. 相似文献
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Characteristics of temperature fluctuation in two-dimensional turbulent Rayleigh-Bénard convection 下载免费PDF全文
We study the characteristics of temperature fluctuation in two-dimensional turbulent Rayleigh–Benard convection in′a square cavity by direct numerical simulations.The Rayleigh number range is 1×108≤Ra≤1×1013,and the Prandtl number is selected as Pr=0.7 and Pr=4.3.It is found that the temperature fluctuation profiles with respect to Ra exhibit two different distribution patterns.In the thermal boundary layer,the normalized fluctuationθrms/θrms,max is independent of Ra and a power law relation is identified,i.e.,θrms/θrms,max~(z/δ)0.99±0.01,where z/δis a dimensionless distance to the boundary(δis the thickness of thermal boundary layer).Out of the boundary layer,when Ra≤5×109,the profiles ofθrms/θrms,max descend,then ascend,and finally drop dramatically as z/δincreases.While for Ra≥1×1010,the profiles continuously decrease and finally overlap with each other.The two different characteristics of temperature fluctuations are closely related to the formation of stable large-scale circulations and corner rolls.Besides,there is a critical value of Ra indicating the transition,beyond which the fluctuation hθrmsiV has a power law dependence on Ra,given by hθrmsiV~Ra?0.14±0.01. 相似文献