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Hong Cai Honglie Shen Linfeng Lu Zhengxia Tang 《Journal of Physics and Chemistry of Solids》2009,70(6):967-971
In the present work, ZnO was deposited on porous silicon substrates by sol-gel spin coating and rf magnetron sputtering. The porous silicon (PS) substrates were formed by electrochemical anodization on p-type (1 0 0) silicon wafer, and the starting material for ZnO was Zinc acetate dehydrate. Raman spectroscopy revealed the good quality of the porous silicon substrate. XRD analysis showed that highly (0 0 2) oriented ZnO thin films were formed. SEM, AFM and optical microscope have been used to understand the effects of the substrate on crystalline properties of the samples. The results indicated that the porous silicon substrate is beneficial to improve the crystalline quality in lattice mismatch heteroepitaxy due to its sponge-like structure. 相似文献
3.
Microstructure and optical properties of nanocrystalline ZnO and ZnO:(Li or Al) thin films 总被引:1,自引:0,他引:1
Zinc oxide thin films (ZnO, ZnO:Li, ZnO:Al) were deposited on glass substrates by a sol-gel technique. Zinc acetate, lithium acetate, and aluminum chloride were used as metal ion sources in the precursor solutions. XRD analysis revealed that Li doped and undoped ZnO films formed single phase zincite structure in contrast to Al:ZnO films which did not fully crystallize at the annealing temperature of 550 °C. Crystallized films had a grain size under 50 nm and showed c-axis grain orientation. All films had a very smooth surface with RMS surface roughness values between 0.23 and 0.35 nm. Surface roughness and optical band tail values increased by Al doping. Compared to undoped ZnO films, Li doping slightly increased the optical band gap of the films. 相似文献
4.
V. S. Zakhvalinskii I. M. Golev L. V. Borisenko T. V. Prokopova A. N. Khmara E. A. Pilyuk D. A. Kolesnikov 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(9):1115-1118
Layers of porous silicon (PS), multilayered ZnO films, and heterostructures based on them are obtained. The surface morphology, chemical and phase composition of the PS layers and ZnO films, and the transverse cleavage of ZnO–PS nanocomposite, are investigated via energy-dispersive X-ray spectral analysis (EDX), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The current–voltage characteristics of Al/Ag/p-Si(100)/PS/ZnO/Ag/Al and Al/Ag/p-Si(100)/PS/ZnO/SiC/Ag/Al heterostructures are studied. 相似文献
5.
Microstructure, magnetic and optical properties of polycrystalline Fe-doped ZnO films fabricated by cosputtering with different Fe atomic fractions (xFe) have been examined systematically. Fe addition could affect the growth of ZnO grains and surface morphology of the films. As xFe is larger than 7.0%, ZnFe2O4 grains appear in the films. All the films are ferromagnetic. The ferromagnetism comes from the ferromagnetic interaction activated by defects between the Fe ions that replace Zn ions. The average moment per Fe ion reaches a maximum value of 1.61 μB at xFe = 4.8%. With further increase in xFe, the average moment per Fe ion decreases because the antiferromagnetic energy is lower than the ferromagnetic one due to the reduced distance between the adjacent Fe ions. The optical band gap value decreases from 3.245 to 3.010 eV as xFe increases from 0% to 10%. Photoluminescence spectra analyses indicate that many defects that affect the optical and magnetic properties exist in the films. 相似文献
6.
S.C. Chen P.C. Kuo A.C. Sun C.Y. Chou Y.H. Fang T.H. Wu 《Journal of magnetism and magnetic materials》2006
An in-plane magnetic anisotropy of FePt film is obtained in the MgO 5 nm/FePt t nm/MgO 5 nm films (where t=5, 10 and 20 nm). Both the in-plane coercivity (Hc∥) and the perpendicular magnetic anisotropy of FePt films are increased when introducing an Ag-capped layer instead of MgO-capped layer. An in-plane coercivity is 3154 Oe for the MgO 5 nm/FePt 10 nm/MgO 5 nm film, and it can be increased to 4846 Oe as a 5 nm Ag-capped layer instead of MgO-capped layer. The transmission electron microscopy (TEM)-energy disperse spectrum (EDS) analysis shows that the Ag mainly distributed at the grain boundary of FePt, that leads the increase of the grain boundary energy, which will enhance coercivity and perpendicular magnetic anisotropy of FePt film. 相似文献
7.
The nitrogen doping of ZnO film deposited by the magnetron sputtering method is subsequently realized by the hydrothermal synthesis method.The nitrogen-doped ZnO film is preferably(002) oriented.With the increase of hexamethylenetetramine(HMT) solution concentration,the average grain size of the film along the 002 direction almost immediately decreases and then monotonously increases,conversely,the lattice strain first increases and then decreases.The structural evolution of the film surface from compact and even to sparse and rough is attributed to the enhanced nitrogen doping content in the hydrothermal process.The transmission and photoluminescence properties of the film are closely related to grain size,lattice strain,and nitrogen-related defect arising from the enhanced nitrogen doping content with HMT concentration increasing. 相似文献
8.
ZnS and ZnO films were prepared on porous silicon (PS) substrates with the same porosity by pulsed laser deposition (PLD), and the structural, optical and electrical properties of ZnS and ZnO films on PS were investigated at room temperature by X-ray diffraction (XRD), scanning electron microscope (SEM), optical absorption measurement, photoluminescence (PL) and I–V characteristic studies. The prepared ZnS was obtained in the cubic phase along β-ZnS (1 1 1) orientation which showed a perfect match with the earlier report while ZnO films were obtained in c-axis orientation. There appeared some cracks in the surface of ZnS and ZnO films due to the roughness of PS substrates. Luminescence studies of ZnS/PS and ZnO/PS composites indicated room temperature emission in a broad, intense, visible photoluminescence band, which cover the blue emission to red emission, exhibiting intensively white light emission. Based on the I–V characteristic, ZnS/PS heterojunction exhibited the rectifying junction behavior, while the I–V characteristic of ZnO/PS heterostructure was different from that of the common diode, whose reverse current was not saturated. 相似文献
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X.D. ZhangP. Wu Y.Y. ShenL.H. Zhang Y.H. XueF. Zhu D.C. ZhangC.L. Liu 《Applied Surface Science》2011,258(1):151-157
The structural and luminescence related optical behaviours of Au ion implanted ZnO films grown by magnetic sputtering and their post implantation annealing behaviours in the temperature range of 100-700 °C have been investigated. Optical absorption and transmittance spectra of the films indicate that band edge of Au-implanted ZnO has shifted to high energy range and optical band gap has increased, because the sharp difference of thermal expansion induces the lattice mismatch between ZnO and SiO2. PL spectra reveal that UV and visible luminescence bands of ZnO films can be improved after thermal annealing due to recovery of defects and Au ions incorporation. Importantly, green luminescence band of 530 nm has been only observed in the Au-implanted and subsequently annealed ZnO films and it enhances with the increasing annealing temperature, which can be related to Au atoms or clusters in ZnO films. Furthermore, X-ray photoelectron spectroscopy measurements reveal that the Au0 is dominant state in Au implanted and annealed ZnO films. Possible mechanisms, such as optical transitions of Au atoms or clusters and deep level luminescence of ZnO, have been proposed for green emission. 相似文献
11.
使用射频磁控溅射法成功制备了不同掺杂浓度(0—7at.%)的ZnO:Ni薄膜.X射线衍射的θ-2θ和摇摆曲线扫描结果表明,5at.%Ni掺杂ZnO薄膜具有沿c轴方向最佳的择优取向生长特性,(002)衍射峰向大角度方向移动揭示了Ni杂质被掺入ZnO晶格中占据Zn位.ZnO:Ni薄膜具有较好的可见光透明特性,拟合发现薄膜的光学带隙随Ni掺杂量的增加由3.272 eV线性降低到3.253 eV.未掺杂薄膜在550 nm处呈现出一个绿色发光峰,掺入Ni杂质后薄膜主要表现了以430 nm为中心的蓝色发光,分析认为它们分别源于薄膜中O空位和Zn填隙缺陷发光.
关键词:
ZnO:Ni薄膜
结构特性
光学带隙
光致发光 相似文献
12.
《Infrared Physics & Technology》1999,40(4):337-342
The structural and electrical characteristics of vacuum deposited PbTe films on Si substrate with buffer porous silicon (PS) layer were investigated. Auger electron spectroscopy, electron and optical microscopy data have shown the absence of cracks, pores, metal and chalcogen microinclusions. A mosaic structure with a grain size of 20–60 μm was detected by selective chemical etching and acoustic microscopy methods. The investigations of X-ray diffraction and X-ray pole figures showed that grains have [100] orientation along the growth direction. The cooling–heating (300–77–300 K) cycles of multilayer PbTe/sublayer/Si structures did not lead to the processes of peeling or appearance of cracks. It was found that thick amorphous layers on a PS surface change the nature of PbTe films growth. 相似文献
13.
A. Boukezzata A. Keffous A. Cheriet N. Gabouze G. Nezzal A. Bright H. Menari 《Applied Surface Science》2010,256(18):5592-5595
In this work, we present the formation of porous layers on hydrogenated amorphous SiC (a-SiC: H) by Ag-assisted photochemical etching using HF/K2S2O8 solution under UV illumination at 254 nm wavelength. The amorphous films a-SiC: H were elaborated by d.c. magnetron sputtering using a hot pressed polycrystalline 6H-SiC target. Because of the high resistivity of the SiC layer, around 1.6 MΩ cm and in order to facilitate the chemical etching, a thin metallic film of high purity silver (Ag) has been deposited under vacuum onto the thin a-SiC: H layer. The etched surface was characterized by scanning electron microscopy, secondary ion mass spectroscopy, infrared spectroscopy and photoluminescence. The results show that the morphology of etched a-SiC: H surface evolves with etching time. For an etching time of 20 min the surface presents a hemispherical crater, indicating that the porous SiC layer is perforated. Photoluminescence characterization of etched a-SiC: H samples for 20 min shows a high and an intense blue PL, whereas it has been shown that the PL decreases for higher etching time. Finally, a dissolution mechanism of the silicon carbide in 1HF/1K2S2O8 solution has been proposed. 相似文献
14.
S. Flickyngerova K. Shtereva D. Hasko V.Tvarozek E. Vavrinsky 《Applied Surface Science》2008,254(12):3643-3647
Zinc oxide (ZnO) and aluminium-doped zinc oxide (ZnO:Al) thin films were prepared by RF diode sputtering at varying deposition conditions. The effects of negative bias voltage and RF power on structural and optical properties were investigated. X-ray diffraction measurements (XRD) confirmed that both un-doped and Al-doped ZnO films are polycrystalline and have hexagonal wurtzite structure. The preferential 〈0 0 1〉 orientation and surface roughness evaluated by AFM measurements showed dependence on applied bias voltage and RF power. The sputtered ZnO and ZnO:Al films had high optical transmittance (>90%) in the wavelength range of 400-800 nm, which was not influenced by bias voltage and RF power. ZnO:Al were conductive and highly transparent. Optical band gap of un-doped and Al-doped ZnO thin films depended on negative bias and RF power and in both cases showed tendency to narrowing. 相似文献
15.
为解决掺杂引起的二氧化钒薄膜的红外调制幅度下降以及二氧化钒复合薄膜相变温度需要进一步降低等问题, 采用纳米结构、掺杂改性和复合结构等多种机理协同作用的方案, 利用共溅射氧化法, 先在石英玻璃上制备高(002)取向的ZnO薄膜, 再在ZnO层上室温共溅射沉积钒钨金属薄膜, 最后经热氧化处理获得双层钨掺杂W-VO2/ZnO纳米复合薄膜. 利用X射线衍射、X射线光电子能谱、扫描电镜和变温光谱分析等对薄膜的结构、组分、形貌和光学特性进行了分析. 结果显示, W-VO2/ZnO 纳米复合薄膜呈花状结构, 取向性提高, 在保持掺杂薄膜相变温度(约39 ℃)和热滞回线宽度(约6 ℃)较低的情况下, 其相变前后的红外透过率差量增加近2倍, 热致变色性能得到协同增强.
关键词:
2')" href="#">VO2
ZnO
W掺杂
热致变色 相似文献
16.
F. Koch D. Kovalev B. Averboukh G. Polisski M. Ben-Chorin 《Journal of luminescence》1996,70(1-6):320-332
We examine the polarization memory effect for porous Si excited by linearly polarized light. The various observations for the red-luminescing, slow band are discussed in the general framework of particle shape asymmetry. We show that because of the intrinsically nonlinear luminescence response, measurement parameters influence the polarization response. The preparation of porous Si with photoassisted etching is found to control the polarization retention parameter ρ. Using linearly polarized light during etching produces in-plane asymmetries. We find a substantial ρ-anisotropy linked to crystal symmetry planes and axes as a consequence of anisotropic etching. The effects are discussed with reference to current models of the light emission mechanism. 相似文献
17.
Sarla Sharma Rishi VyasSubodh Shrivastava Y.K. Vijay 《Physica B: Condensed Matter》2011,406(17):3230-3233
We report a study on the SHI induced modifications on structural and optical properties of ZnO/PMMA nanocomposite films. The ZnO nanoparticles were synthesized by the chemical route using 2-mercaptoethanol as a capping agent. The structure of ZnO nanoparticles was confirmed by XRD, SEM and TEM. These ZnO nanoparticles were dispersed in the PMMA matrix to form ZnO/PMMA nanocomposite films by the solution cast method. These ZnO/PMMA nanocomposite films were then irradiated by swift heavy ion irradiation (Ni8+ ion beam, 100 MeV) at a fluence of 1×1011 ions/cm2. The nanocomposite films were then characterized by XRD, UV-vis absorption spectroscopy and photoluminescence spectroscopy. As revealed from the absorption spectra, absorption edge is not changed by the irradiation but the optical absorption is increased. Enhanced green luminescence at about 527 nm and a less intense blue emission peak around 460 nm were observed after irradiation with respect to the pristine ZnO/PMMA nanocomposite film. 相似文献
18.
Photoluminescence and electroluminescence properties of ZnO films on p-type silicon wafers 下载免费PDF全文
A simplified n-ZnO/p-Si heterojunction has been prepared by growing
n-type ZnO rods on p-type silicon wafer through the chemical vapour
deposition method. The reflectance spectrum of the sample shows an
independent absorption peak at 384 nm, which may be originated from
the bound states at the junction. In the photoluminescence spectrum a
new emission band is shown at 393 nm, besides the bandedge emission
at 380 nm. The electroluminescence spectrum of the n-ZnO/p-Si
heterojunction shows a stable yellow luminescence band centred at 560
nm,which can be attributed to the emission from trapped states.
Another kind of discrete ZnO rod has also been prepared on such
silicon wafer and is encapsulated with carbonated polystyrene for
electroluminescence detection. This composite structure shows a weak
ultraviolet electroluminescence band at 395 nm and a yellow
electroluminescence band. These data prove that surface modification
which blocks the transverse movement of carriers between neighbouring
nanorods plays important roles in the ultraviolet emission of ZnO
nanorods. These findings are vital for future display device design. 相似文献
19.
通过脉冲激光沉积(PLD)法在SiO2基片上制备了不同含量的Mn掺杂ZnO薄膜.X射线衍射、X射线能谱、原子力显微镜与紫外-可见分光光度计测试结果表明:少量的Mn离子的掺杂并没有改变薄膜的结构,薄膜具有(103)面的择优取向;PLD法制备的ZnO薄膜的成分与靶材基本一致,实现了薄膜的同组分沉积;薄膜表面比较平坦,起伏度小于80nm,颗粒尺寸主要集中在25nm附近;但是Mn离子的掺杂改变了ZnO薄膜的禁带宽度,随Mn掺杂含量的增加,ZnO薄膜的禁带宽度增加;当薄膜中Mn含量从6%增加到
关键词:
PLD
ZnO薄膜
Mn掺杂
吸收谱 相似文献
20.
采用一种设备简单、原料低廉的新型方法,在镀有ZnO先驱薄膜的(0001)蓝宝石上利用水热 法制备出了柱状ZnO阵列薄膜.用扫描电镜(SEM),X射线衍射(XRD)对样品的形貌和结构进行 了表征,结果显示ZnO薄膜为柱状阵列,基于蓝宝石衬底沿c轴择优生长,且(0004)摇摆曲线 半高宽度(FWHM)约为1.8°.此ZnO阵列薄膜具有很强的紫外发射光谱(PL).
关键词:
柱状ZnO阵列薄膜
水热法
(0001)蓝宝石
PL谱 相似文献