987 resultados para PL
Resumo:
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).
Resumo:
ZnO thin films were deposited on the substrates of (100) gamma-LiAlO2 at 400, 550 and 700 degrees C using pulsed laser deposition (PLD) with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400 degrees C, the grain size of the film is less than 1 mu m observed by Leitz microscope and measured by X-ray diffraction (XRD). As the substrate temperature increases to 550 degrees C, highly-preferred c-orientation and high-quality ZnO film can be attained. While the substrate temperature rises to 700 degrees C, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence (PL) spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on gamma-LiAlO2 (LAO) exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li. from the substrates into the films during the deposition.
Resumo:
用脉冲激光沉积法在MgO(100)衬底上沉积了ZnO薄膜.衬底温度分别为400℃、550℃和700℃.利用X射线衍射(XRD)和光致发光谱(PL)对薄膜的结构和光学性能进行研究.x射线衍射的结果表明,在400℃和550℃下生长的ZnO薄膜具有高度c一轴择优取向.仉足当衬底温度升高到700℃时,薄膜由单一的择优取向变为有两个较强的择优取向.通过光致发光谱可以发现,在550℃下生长的ZnO薄膜具有强的紫外发射和窄的FWHM,并且紫外发光峰的强度与ZnO薄膜的结晶质量密切相关.
Resumo:
采用溶胶-凝胶法制备了不同组分(x=0.1—0.3)的MgxZn1-xO前驱体,并对它进行不同温度的热处理(550℃-1000℃)。X射线衍射(XRD)结果表明,Mg0.1Zn0.9O具有和ZnO一样的衍射谱,为六方纤锌矿结构,而且随着热处理温度的升高,ZnO衍射峰的强度逐渐增强,半高宽不断减小;Mg元素掺杂浓度增大后,出现了MgO的峰位。扫描电子显微镜(SEM)显示Mg0.1Zn0.9O晶粒粒径分布较均匀;热处理温度升高,晶粒的尺寸不断变大。用室温荧光光谱(PL)分析了经过550—1000℃热处理获得的
Resumo:
用脉冲激光沉积法在Al2O3(0001)衬底上沉积了ZnO薄膜。衬底温度分别为300℃、400℃、500℃、600℃和700℃。利用X射线衍射(XRD)和光致发光谱(PL)对薄膜的结构和光学性能进行研究。X射线衍射的结果表明在不同温度下生长的ZnO薄膜均具有高度c轴择优取向,衬底温度400℃时,膜的应力较小质量较高。ZnO薄膜有很强的紫外发光峰,紫外发光峰的强度与衬底温度密切相关,并发现当衬底温度从300℃增到400℃时,紫外发射峰出现6nm的蓝移。
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Spectroscopic properties of Ce-doped yttrium orthoaluminate (Ce:YAlO3 or Ce:YAP) crystals grown by temperature gradient technique (TGT) were investigated, and the effects of the growth conditions on the properties were analyzed.. Methods of optical absorption (OA), photoluminescence (PL), photoluminescence decay (PLD), X-ray excited luminescence (XL) and cathodeluminescence (CL) were used in these investigations. The results showed that the absorption band peak at 202, 394 and 532 nm originated from F and F+ color center induced by the weak reducing growth atmosphere, green emission band near 500 ran derived from Ce3+ -Ce3+ pairs and band at 650 similar to 850 run from some unintentional impurity in crystals.
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用脉冲激光淀积法(PLD)在(111)面SrTiO3衬底上外延生长ZnO单晶薄膜。样品分别在衬底温度为350℃、500℃、600℃下外延生长。X射线衍射(XRD)的结果表明,所得的ZnO单晶薄膜结晶性能好,只出现(002)和(004)两个衍射峰,(002)峰的半高宽度(FWHM)为0.23°。在荧光光谱中我们只观察到来源于带边激子跃迁的强UV发射,并且随着生长温度的升高,紫外峰的强度逐渐增强。样品的SEM图像表明所得ZnO薄膜表面平整,晶粒均匀。衬底温度为600℃时,所得到的ZnO薄膜结构完整,晶粒尺寸最
Resumo:
本文采用两步湿化学法在玻璃衬底上制备了ZnO纳米线.首先,利用Sol-gel方法在载玻片上制备含有ZnO纳米颗粒的薄膜作为“种子”衬底.然后,利用水热法在“种子”衬底上生长了高度取向的ZnO纳米线.并对“种子”衬底和随后生长的ZnO纳米线进行了X射线衍射(XRD)、扫描电子形貌图(SEM)和原子力显微镜(AFM)等分析.结果表明“种子”衬底为大范围内纳米颗粒均匀一致的ZnO 薄膜.通过水热法制备的ZnO纳米线的直径在50~80nm,平均直径为60nm,长度大约为2μm.该ZnO纳米线除了具有很强的紫外发光
Resumo:
利用激光脉冲沉积(PLD)技术在(302)γ-LiAIO2衬底上成功生长了非极性的a面(112^-0)γZnO薄膜.衬底温度为350℃时,薄膜是混合取向(a向和C向),以c面ZnO为主,且晶粒尺寸分布很宽;提高温度达500℃,薄膜变为单一的(1120)取向,摇摆曲线半高宽O.65^o,晶粒尺寸分布趋窄,利用偏振透射谱可以明显看出其面内的各向异性.衬底温度650℃下制备的样品晶粒继续长大,虽然摇摆曲线半高宽变大,但光致发光谱(PL)带边发射峰半高宽仅为105meV,比在350℃,500℃下制备的样品小1/5
Resumo:
采用磁控溅射法在(001)、(100)及(010)LiGaO2衬底上制备了ZnO薄膜,通过X射线衍射(XRD)、原子力显微镜(AFM)、透过光谱以及光致发光谱(PL)对薄膜的结构、形貌及光学性质进行了表征。结果表明LiGaO2衬底不同晶面上制备的ZnO薄膜具有不同的择优取向,在(001)(、100)及(010)LiGaO2上分别获得了[0001][、1100]及[1120]取向的ZnO薄膜;不同取向的ZnO薄膜表面形貌差异较大;薄膜在可见光波段具有较高的透过率;在ZnO薄膜的光致发光谱中只观察到了位于378 nm的紫外发射峰,而深能级发射几乎观察不到,(1100)取向的薄膜紫外发射峰强度最大,半高宽也最小,薄膜光致发光性质的差异主要和晶粒尺寸有关。
Resumo:
ZnO crystals with dimensions of 30 x 38 x 8 turn 3 have been grown by the hydrothermal method using a mixed solution of KOH, LiOH and H2O2. The growing rates for +c(0001) and -c(000 (1) over bar) were 0.17 and 0.09 mm/day, respectively. The crystal color was very light green for +c sector and dark brown for -c sector. For the +c sector, the resistivity at room temperature was 80 0 cm, the carrier concentration was about 10(4)/cm(3), and the mobility was about 100 cm(2)/Vs. The full-width at half-maximum (FWHM) of double axis X-ray rocking curve for the polished Zn face cut from +c sector was 45 arcsec. The photoluminescence (PL) spectrum and the absorption spectrum of +c part of the crystals at room temperature were also reported and discussed in this paper. (c) 2008 Elsevier B.V. All rights reserved.
Resumo:
ZnO films were fabricated on LiGaO2 (0 0 1), (10 0) and (0 10) planes by RF magnetron sputtering. The structural, morphological and optical properties of as-grown ZnO films were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectra and photoluminescence (PL) spectra. It is found that the orientation of ZnO films is strongly dependent on the substrate plane. [0 0 0 11, [1 (1) over bar 00] and [11 (2) over bar0] oriented ZnO films are deposited on LiGaO2 (001), (100) and (010), respectively. AFM shows the (0001) ZnO film consists of well-aligned regular hexagonal grains. Raman spectra reveal a tensile stress in the (0 0 0 1) ZnO film and a compressive stress in (110 0) and (112 0) ZnO films. PL spectra of all ZnO films exhibit only a near-band-edge UV emission peak. (C) 2008 Elsevier B.V. All rights reserved.
Resumo:
利用激光脉冲沉积(PLD)技术在(302)γ-LiAlO2衬底上成功生长了非极性的a面(1120)ZnO薄膜,光致发光谱(PL)带边发射峰半峰宽仅为115meV.研究了非极性ZnO薄膜光谱特性的面内各向异性,发现随着入射光偏振方向改变,在偏振透射光谱上,吸收边移动了20meV,这与A、B激子和C激子的能量差一致;而在拉曼光谱上,激发光偏振方向的改变导致E2模式的强度发生明显改变.
Resumo:
A series of ZnO thin films were deposited on ZnO buffer layers by DC reactive magnetron sputtering. The buffer layer thickness determination of microstructure and optical properties of ZnO films was investigated by X-ray diffraction (XRD), photoluminescence (PL), optical transmittance and absorption measurements. XRD results revealed that the stress of ZnO thin films varied with the buffer layer thickness. With the increase of buffer layer thickness, the band gap edge shifted toward longer wavelength. The near-band-edge (NBE) emission intensity of ZnO films deposited on ZnO buffer layer also varied with the increase of thickness due to the spatial confinement increasing the Coulomb interaction between electrons and holes. The PL measurement showed that the optimum thickness of the ZnO buffer layer was around 12 nm. (c) 2005 Elsevier B.V. All rights reserved.
Resumo:
Zinc oxide (ZnO) films with c-oriented were grown on fused quartz glass substrates at room temperature using dc reactive magnetron sputtering. The as-grown films were annealed at 700 degrees C in air and bombarded by ion beam, respectively. The effects of post-treatments on the structural and optical properties of the ZnO films were investigated by X-ray diffraction (XRD), photoluminescence (PL), optical transmittance and absorption measurements. The XRD spectra indicate that the crystal quality of ZnO films has been improved by both the post-treatments. Compared with the as-grown sample, both annealed and bombarded samples exhibited blueshift in the UV emission peaks, and a strong green emission was found in the annealed ZnO film. In both optical transmittance and absorption spectra, a blueshift of the band-gap edge was observed in the bombarded film, while a redshift was observed in the annealed film. (c) 2004 Elsevier B.V. All rights reserved.