排序方式: 共有68条查询结果,搜索用时 15 毫秒
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为获得与GaN薄膜晶格失配小的衬底材料,报道了利用气相传输平衡技术(VTE)在(100)-βGa2O3单晶衬底上制备高度[001]取向LiGaO2薄膜的方法。经过X射线衍射分析表明得到的薄膜是由单相LiGaO2组成。利用扫描电镜(SEM)观察表面形貌,发现经气相传输平衡技术处理得到的薄膜表面形貌主要受温度的影响,表面晶粒尺寸随温度上升而增大。而X射线衍射测试表明随着温度上升,所得到的薄膜也从多晶向单晶化转变。在经过退火处理后,通过观察吸收谱发现LiGaO2薄膜中产生色心,并且色心的种类与温度有关。表明可以通过气相传输平衡技术技术,在远低于LiGaO2熔点的温度制备外延GaN用(001)LiGaO2∥(100)β-Ga2O3复合衬底。 相似文献
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采用快速提拉法生长出了透明、完整的γ-LiAlO2晶体,但是晶体的高熔点和易 挥发性限制了γ-LiAlO2晶体质量.采用气相传输平衡法(vapor transport equilibra tion technique,VTE)工艺对晶体改性,半高宽(FWHM)值从1169arcsec降至442arcsec,继续升高VTE处理温度至1300℃,FWHM值反而升高至552arcsec.快速提拉法生长出来晶体,100]方向和[001]方向的热膨胀系数分别为172398×10-6/K,107 664×10-6/K.经过三步VTE处理后[100]和[001]方向热膨胀系数降至16 6539×10-6/K和101784×10-6/K.
关键词:
2')" href="#">γ-LiAlO2
气相传输平衡法
热膨胀系数 相似文献
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La0.67Ca0.33MnO3多晶的本征和非本征磁电阻 总被引:1,自引:0,他引:1
研究了不同烧结温度的La0.67Ca0.33MnO3多晶块材的电磁输运特性.在ρ~T曲线上居里温度Tc以下的温区,观察到一个宽化的峰.讨论了Tc附近及其以下的本征和非本征磁电阻效应并将它们分解开来. 相似文献
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The resurgence in the study of ZnO continues. The now ready availability of good-quality single crystals and films[1,2] and discovery of lasing action in the materials[3] have generated new life in an old material. A direct semi- conductor with a gap energy of 3.3 eV[4], ZnO is in the position of being able to offer a challenge to GaN in the blue laser market[5]. The advantages of ZnO are the high quality of the material and the large exciton bind- ing energy (60 meV). The large exciton bi… 相似文献
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凝胶-燃烧法合成YAG∶Eu3+纳米荧光材料的结构和发光性能 总被引:6,自引:0,他引:6
Y3Al5O12∶Eu nanophosphors were synthesized by a gel combustion method. The structure of phosphors was characterized by XRD and FTIR. YAG phase came to occur when YAG∶Eu precursors were sintered at 800 ℃, although the phase was mainly amorphous. The organic groups pyrolyzed completely and pure YAG phase was obtained in the samples sintered at 900 ℃. In the formation of YAG phase, no intermediate phases such as YAP and YAM were detected. Both 5D0 → 7F1 orange and 5D0 → 7F2 red emission could be observed for all the sintered samples. However, the emission of amorphous samples was greatly different from that of crystalline ones. The former was mainly 5D0→ 7F2 red emission, but the latter was 5D0 → 7F1 orange emission. As sintering temperature rises, the ratio of orange to red for phosphors increases. Eu could be doped up to 8% in YAG host lattice, and fluorescence quenching was absent. It indicated that the gel combustion synthesis method can increase emission intensity and quenching concentration due to a good distribution of Eu3+ activators in Y3Al5O12 matrix. 相似文献
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退火处理对ZnO薄膜发光特性的影响 总被引:3,自引:1,他引:3
用脉冲激光沉积法(PLD)在MgO(100)、a-Al2O3(0001)和MgAl2O4(111)衬底上沉积了ZnO薄膜,测量了它们的发射光谱,观察到430nm的蓝光发射,并研究了退火、衬底和激发波长对ZnO薄膜这一蓝光发射的影响。指出ZnO薄膜中430nm的蓝光发射是由锌填隙原子缺陷能级到价带顶能级间的跃迁以及电子从氧空位浅施主能级到价带顶能级间的跃迁两种机理共同作用的结果。在MgO衬底上沉积的ZnO薄膜在350nm光激发下蓝光发射峰最强。 相似文献
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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,晶粒尺寸最大,均匀;而且紫外发射最强。 相似文献
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This paper reports that the m-plane GaN layer is grown on (200)-plane LiAlO2 substrate by metal-organic chemical wpour deposition (MOCVD) method. Tetragonal-shaped crystallites appear at the smooth surface. Raman measurement illuminates the compressive stress in the layer which is released with increasing the layer's thickness. The high transmittance (80%), sharp band edge and excitonic absorption peak show that the GaN layer has good optical quality. The donor acceptor pair emission peak located at -3.41 eV with full-width at half maximum of 120 meV and no yellow peaks in the photoluminescence spectra partially show that no Li incorporated into GaN layer from the LiAlO2 substrate. 相似文献