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1.
本文报道了a-Si:H/a-SiNx:H超晶格薄膜光致发光某些性质的研究。实验发现,这种超晶格薄膜光致发光的强度和峰值能量随交替层a-Si:H厚度,测量温度及光照时间等而变化。同时还发现,在阴、阳两极上,利用GD法沉积的样品,发光强度和峰值能量也有所不同。文中对这些实验结果作了初步解释。 相似文献
2.
X. Portier C. Ternon F. Gourbilleau C. Dufour R. Rizk 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):439
Photoluminescence spectroscopy, Fourier transform infrared spectroscopy, X-ray reflectometry and high resolution electron microscopy have been used to interpret the photoluminescence properties of annealed (3/19 nm) Si/SiO2 multilayers grown by reactive magnetron sputtering. The multilayers show an emission in the visible and near-infrared range after heat treatment from 900°C which tends to decrease from 1200°C. Three different origins for the photoluminescence activity have been found. An anneal temperature of 1200°C is necessary to optimise the silicon crystallisation within the silicon sublayers. 相似文献
3.
R.B. Wehrspohn J.-N. Chazalviel F. Ozanam I. Solomon 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,8(2):179-193
Light-emitting porous amorphous silicon has been produced by anodization in HF of hydrogenated amorphous silicon films. The
maximal thickness of the porous films is limited by the onset of an instability which results in the formation of large channels
short-circuiting the amorphous layer. This is due to the high resistivity of the amorphous silicon films as compared to that
of the electrolyte. Confinement effects on the electron wavefunction are analyzed in situ using photoluminescence measurements in hydrofluoric acid and compared to those observed in porous crystalline silicon. For
crystalline silicon, a huge blue shift of the photoluminescence is observable upon reducing the size of the structures by
photo-etch, showing clear evidence of quantum confinement effects in this material. No shift has been observed when carrying
out the same experiment with amorphous silicon. This indicates that the extent of the wavefunction in the bandtail states
involved in luminescence is too small to be sensitive to confinement down to the minimum sizes of our porous material ( 3 nm). Measurements of the width and the temperature dependence of the photoluminescence demonstrate that the Urbach energy
does not change upon increasing the porosity, i.e., upon decreasing the size of the a-Si:H nanostructures, in contradiction with what has been reported in ultrathin a-Si:H multilayers.
Received: 3 August 1998 相似文献
4.
O. B. Gusev J. S. Vainshtein Yu. K. Undalov O. S. Yeltsina I. N. Trapeznikova E. I. Terukov O. M. Sreseli 《JETP Letters》2011,94(5):370-373
Films of amorphous silicon suboxide α-SiO
x
containing amorphous silicon nanoclusters have been grown by direct current magnetron sputtering. It has been found that
two radiation bands are observed in the photoluminescence spectra of relatively large amorphous nanoclusters (a size of ∼2
nm) unlike one photoluminescence band of silicon nanocrystals of the same size. The form of the spectra upon the change in
the nanocluster sizes agrees with that predicted in theoretical works, in which the energy spectrum of amorphous nanoclusters
has been calculated taking into account quantum confinement of delocalized, weakly localized, and strongly localized states. 相似文献
5.
In order to determine the causes reducing or destroying the stability of the multilayers which consist the essential parts of satellite mirrors, an experimental study, based on deflection tests has been performed. The observed temperature induced deflections are discussed in relation to diffusion controlled mechanisms producing microstructural changes in the multilayer. The deflections were observed when annealing the multilayers up to 573 K, in a pure argon or oxygen atmosphere.The multilayers consisted in successive thin films, deposited on a 〈0 0 1〉 silicon substrate: first a 30 nm thick amorphous silica layer, then a metallic film, made of nickel or chromium, and finally a silver layer which ensures the reflective properties.It was verified that the metal glass interface remained stable during heat-treatments, while other diffusion controlled mechanisms could degrade the multilayers. Among them: the oxidation of the metallic layer, possible solid state reaction forming Ni2Si, and well identified agglomerations of the silver layer with formation of hillocks and unwetted zones. 相似文献
6.
D. I. Tetelbaum A. N. Mikhaylov A. I. Belov V. K. Vasiliev A. I. Kovalev D. L. Wainshtein Y. Golan A. Osherov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2009,3(5):702-708
Luminescent and structural characteristics of SiO2 layers exposed to double implantation by Si+ and C+ ions in order to synthesize nanosized silicon carbide inclusions have been investigated by the photoluminescence, electron spin resonance, transmission electron microscopy, and electron spectroscopy methods. It is shown that the irradiation of SiO2 layers containing preliminary synthesized silicon nanocrystals by carbon ions is accompanied by quenching the nanocrystal-related photoluminescence at 700–750 nm and by the enhancement of light emission from oxygen-deficient centers in oxide in the range of 350–700 nm. Subsequent annealing at 1000 or 1100°C results in the healing of defects and, correspondingly, in the weakening of the related photoluminescence peaks and also recovers in part the photoluminescence of silicon nanocrystals if the carbon dose is less than the silicon dose and results in the intensive white luminescence if the carbon and silicon doses are equal. This luminescence is characterized by three bands at ~400, ~500, and ~625 nm, which are related to the SiC, C, and Si phase inclusions, respectively. The presence of these phases has been confirmed by electron spectroscopy, the carbon precipitates have the sp 3 bond hybridization. The nanosized amorphous inclusions in the Si+ + C+ implanted and annealed SiO2 layer have been revealed by high-resolution transmission electron microscopy. 相似文献
7.
Do Young Kim Ji Sim Jung Young Rae Jang Kun Ho Yoo Jin Jang 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):400
We studied the growth of nanocrystalline silicon (nc-Si) thin film exhibiting a strong room temperature photoluminescence (PL) at 1.81–2.003 eV. The amorphous silicon was crystallized by Ni silicide mediated crystallization (Ni SMC) and then Secco-etched to exhibit the PL. The PL peak energy and intensity increase with increasing the metal density on the a-Si because of the reduction in the grain size down to 2 nm. The photoluminescence energy and peak intensity depend strongly on the Secco etch time because the grain size is reduced by etching the grain boundaries. 相似文献
8.
采用在等离子体增强化学汽相沉积系统中沉积a-Si:H和原位等离子体逐层氧化的方法制备a-Si:H/SiO2多层膜.改变a-Si:H层的厚度,首次在室温下观察到来自a-Si:H/SiO2多层膜较强的蓝色光致发光和从465到435nm的蓝移.x射线能谱证明,SiO2层是化学配比的SiO2;C-V特性表明,a-Si:H/SiO2界面得到了很好的钝化;透射电子显微镜表明,样品形成了界面陡峭的多层结构.结合光吸收谱和光致发光谱的研究,对其发光机理进行了讨论.用一维量子限制模型对光致发光峰随着a-Si:H层厚度的减小
关键词:
a-Si:H/SiO2多层膜
光致发光 相似文献
9.
We have studied luminescence properties and microstructure of 20 patterns Si/SiO2 multilayers. The photoluminescence spectra consist of two gaussian bands in the visible-infrared spectral region. It has been demonstrated that the strong PL band is caused by the radiative recombination in the Si/SiO2 interfaces states, whereas the weaker band originates from radiative recombination in the nanosized Si layers. The peak shift of this latter band shows a discontinuity that corresponds to a crystalline-to-amorphous phase change when the Si layers are thinner than 30 Å. The peak energy as a function of the layer thickness is interpreted using a quantum confinement model in the case of amorphous Si layers. 相似文献
10.
The evolution of the interphase boundary morphology during annealing of nanoscale metallic A/B multilayers is studied by means of Monte Carlo simulations based on a vacancy migration algorithm. The two components A and B are supposed to be largely immiscible. As initial condition for the simulations, it is assumed that a thermally induced destruction of polycrystalline multilayers starts at grain boundaries by breakthrough of one component through layers of the other one. Simulations of the subsequent development of the phase morphology within the multilayer grains reveal a recession of broken layers which leads to a localised fusion with adjacent layers of the same component. The evolving morphology depends sensitively on the rate of initial layer breakthrough at grain boundaries compared to the velocity of layer recession. Formation and subsequent growth of pinhole-like layer breakthroughs within multilayer grains are proposed as additional mechanisms of multilayer destruction, which should become important at higher temperatures for large lateral grain size and thin individual layers of a few monolayers thickness. 相似文献
11.
Enhanced photoluminescence (PL) at room temperature from thermally annealed a-Si:H/SiO2 multilayers is observed through the step-by-step thermal post-treatment. The correlation between the PL and the crystallization process is studied using temperature-dependent PL, Raman, cross section high-resolution transmission electron microscopy (XHRTEM) and x-ray diffraction (XRD) techniques. An intensified PL band around 820 nm is discovered from the sample annealed near the crystallization onset temperature, which is composed of two peaks centred at 773 nm and 863 nm, respectively. It is found that the PL band centred at 863 nm is related to the pseudo nanocrystal (p-nc-Si) silicon, and the PL band centred at 773 nm is attributed to Si = O bonds stabilized in the p-nc-Si surface. 相似文献
12.
Er-doped SiO single layer and Er-doped SiO/SiO2 multilayers with different SiO thicknesses were prepared by evaporation. In the as-deposited samples, the erbium ions exhibit a very weak photoluminescence emission at 1.54 μm. This luminescence is strongly enhanced after annealing treatments between 500 and 1050 °C, with an optimal annealing temperature which is dependent from the SiO thickness. For the SiO single layer, this optimal temperature is around 700 °C while it is shifted at highest temperature for the multilayers. The origin of the higher luminescence intensity in the SiO layer is also discussed. 相似文献
13.
14.
B.M. Monroy J. Aguilar-Hernández J. Fandiño G. Contreras-Puente J.C. Alonso 《Journal of luminescence》2006,121(2):349-352
Very thin (nanometric) silicon layers were grown in between silicon nitride barriers by SiH2Cl2/H2/NH3 plasma-enhanced chemical vapor deposition (PECVD). The multilayer structures were deposited onto fused silica and silicon substrates. Deposition conditions were selected to favor Si cluster formation of different sizes in between the barriers of silicon nitride. The samples were thermally treated in an inert atmosphere for 1 h at 500 °C for dehydrogenation. Room-temperature photoluminescence (RT-PL) and optical transmission in different ranges were used to evaluate the optical properties of the structures. UV-VIS absorption spectra present two band edges. These band edges are well fitted by the Tauc model typically used for amorphous materials. RT-PL spectra are characterized by strong broad bands, which have a blue shift as a function of the deposition time of the silicon layer, even for as-grown samples. The broad luminescence could be associated with the confinement effect in the silicon clusters. After annealing of the samples, the PL bands red shift. This is probably due to the thermal decomposition of N-H bonds with further effusion of hydrogen and better nitrogen passivation of the nc-Si/SiNx interfaces. 相似文献
15.
A new method is suggested for fabricating nanocrystalline silicon by using high-dose irradiation with rare-gas ions. In this case, a nanostructure is formed due to silicon self-assembling on the interface between amorphous layer and crystalline substrate. Two bands, at 720 and 930 nm, are found in the photoluminescence spectrum. These bands possibly originate from the quantum confinement effects in nanocrystals and may also be related to the regions of disordered silicon outside the amorphous layer containing nanocrystals. The intensity of the photoluminescence signal is studied as a function of duration of HF etching of samples and their subsequent exposure to atmosphere. The influence of thermal annealing on the photoluminescence spectrum is also studied.
相似文献
16.
Optical and photoluminescence characterizations were performed on nanometric multilayer structures based on amorphous silicon nitrogen alloys. Evidences are shown that the radiative efficiency of multilayers increases with respect to single-layer structures. This is ascribed to a strong electron–hole pair localization and a low heterointerfaces defect density. Time-resolved photoluminescence measurements yield fast recombination with an energy-dependent lifetime due to hopping processes. Finally, the performance of an electroluminescent device based on multilayers is presented. 相似文献
17.
Group-IV nanocluster formation by ion-beam synthesis 总被引:1,自引:0,他引:1
W. Skorupa L. Rebohle T. Gebel 《Applied Physics A: Materials Science & Processing》2003,76(7):1049-1059
A short review of our investigations devoted to the use of ion-beam-synthesized nanoclusters for silicon-based light emission
and nonvolatile memory effects is presented. Blue-violet light emission is demonstrated based on Ge-implanted silicon dioxide
layers thermally grown on silicon substrates. This version of silicon-based light emission relies on Ge-related defects in
the amorphous ≡Si–O–Si≡ network. The photoluminescence and electroluminescence are excited by a singlet S0–S1 transition of a neutral oxygen vacancy and by electron injection from the silicon substrate into the silicon dioxide layer,
respectively. Whereas the photoluminescence excitation is a well-known mechanism, for the case of electroluminescence an interpretation
was performed for the first time in the course of our studies. It was found that the most probable way to excite luminescence
centers is the impact excitation by hot electrons. Whereas the injection is explained by trap-assisted tunneling of electrons
from the substrate into the oxide, the electrons will be transported via traps or in the SiO2 conduction band. The application of the silicon-based light-emitting devices for an integrated optocoupler arrangement is
described. Another application of nanoclusters is based on the investigation of thin Si-implanted silicon dioxide layers for
nonvolatile memory devices. First promising results demonstrate that the observed programming window can reach several volts
and the devices exhibit excellent retention behavior. A 256 K-nv-SRAM is demonstrated showing a programming window of >1 V
for write pulses of 12 V/8 ms.
Received: 21 August 2002 / Accepted: 21 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-351/260-3411, E-mail: w.skorupa@fz-rossendorf.de 相似文献
18.
Transitions of microstructure and photoluminescence properties of the Ge/ZnO multilayer films in certain annealing temperature region 总被引:1,自引:0,他引:1
Tianhang Zheng Ziquan Li Jiankang Chen Kai Shen Kefei Sun 《Applied Surface Science》2006,252(24):8482-8486
The Ge/ZnO multilayer films have been prepared by rf magnetron sputtering. The effects of annealing on the microstructure and photoluminescence properties of the multilayers have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectrometry and photoluminescence (PL) spectrometry. The investigation of structural properties indicates that Zn2GeO4 has been formed with (2 2 0) texture and Zn deficiency from Ge/ZnO multilayer films in the process of annealing. However, lower Zn/Ge ratio can be improved by annealing. The annealed multilayers show three main emission bands at 532, 700, and 761 nm, which originate from the transition between oxygen vacancy () and Zn vacancies (VZn), the radiative recombination of quantum-confined excitons (QCE) in Ge nanocrystals, and the optical transition in the GeO color centers, respectively. Finally, the fabrication of thin film Zn2GeO4 from Ge/ZnO multilayer films by annealing at low temperature provides another approach to prepare the green-emitting oxide phosphor film:Zn2GeO4:Mn. 相似文献
19.
脉冲激光退火纳米碳化硅的光致发光 总被引:3,自引:0,他引:3
采用XeCl准分子脉冲激光退火技术制备了纳米晶态碳化硅薄膜(nc-SiC),并对薄膜的光致发光(PL)特性进行了分析。结果表明,纳米SiC薄膜的光致发光表现为300~600 nm范围内的较宽发光谱带,随退火激光能量密度的增加,nc-SiC薄膜398 nm附近的发光峰相对强度增加,而470 nm附近发光峰相对减小。根据nc-SiC薄膜的结构特性变化, 认为这两个发光峰分别来源于6H-SiC导带到价带间的复合发光和缺陷态发光,并且这两种发光过程存在竞争。 相似文献
20.
W. Yu J. Y. Zhang W. G. Ding G. S. Fu 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(1):53-56
We have investigated the photoluminescence (PL)
properties of amorphous silicon nanoparticles (a-Si NPs) embedded in silicon
nitride film (Si-in-SiNx) grown by helicon wave plasma-enhanced
chemical vapor deposition (HWP-CVD) technique. The PL spectrum of the film
exhibits a broad band constituted of two Gaussian components. From
photoluminescence excitation (PLE) measurements, it is elucidated that the
two PL bands are associated with the a-Si NPs and the silicon nitride matrix
surrounding a-Si NPs, respectively. The existence of Stokes shift between PL
and absorption edge indicates that radiative recombination of carriers
occurs in the states at the surface of the Si NPs, whereas their generation
takes place in the a-Si NPs cores and the silicon nitride matrix,
respectively. The visible PL of the film originates from the radiative
recombination of excitons trapped in the surface states. At decreasing
excitation energy (Eex), the PL peak energy was found
to be redshifted, accompanied by a narrowing of the bandwidth. These results
are explained by surface exciton recombination model taking into account
there existing a size distribution of a-Si NPs in the silicon nitride
matrix. 相似文献