共查询到14条相似文献,搜索用时 187 毫秒
1.
利用激光干涉结晶方法,采用周期为400 nm的一维(1D)移相光栅掩模调制KrF准分子激光器的脉冲激光束斑的能量分布,在不同厚度的超薄氢化非晶硅(a-Si:H)膜内直接制备1D有序纳米硅(nc-Si)阵列.拉曼散射谱表明,样品上呈条状分布的受辐照区域发生晶化.原子力显微镜和透射电子显微镜测试结果表明:1D的nc-Si阵列的周期和移相光栅掩模一样.随着a-Si:H膜厚度从10nm降至4nm,通过控制激光的能量密度,每个周期中nc-Si条状分布区宽度可达到30nm.nc-Si条状分布区的高分辨电子显微镜照片显
关键词:
纳米硅
激光干涉结晶
移相光栅
定域晶化 相似文献
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从菲涅耳衍射积分的一般形式出发,结合二维(2D)移相光栅掩模(PSGM)的具体参数,通过数值计算得到了作用于样品表面的光强分布.实验上,采用激光干涉晶化的方法,利用周期为400 nm的2D-PSGM调制KrF准分子激光器的脉冲激光束斑的能量分布,在氢化非晶硅(a-Si:H)薄膜上直接制备了2D的有序纳米硅(nc-Si)阵列.测试结果表明:2D的nc-Si阵列的周期和PSGM的相一致,晶化区域与理论模拟的结果符合得很好.
关键词:
纳米硅
激光干涉晶化
移相光栅
菲涅耳衍射 相似文献
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在等离子体增强化学气相淀积(PECVD)系统中,采用a-Si∶H层淀积与原位等离子体氧化相结合的逐层生长的方法成功制备出a-Si∶H/SiO2多层膜 (ML);利用限制性结晶原理通过两步退火处理使a-Si∶H层晶化获得尺寸可控的nc-Si/SiO2 ML,并观察到室温下的蓝光发射;结合Raman散射和剖面透射电子显微镜技术分析了nc-Si/SiO2 ML的结构特性;通过对晶化样品光致发光谱和紫外-可见光吸收谱的研究,探讨了蓝光发射的起源.
关键词:
纳米硅多层膜
等离子体氧化
蓝光发射
热退火 相似文献
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基于经典热力学理论,对a-SiNx/a-Si:H/a-SiNx三明治结构或a-Si:H/a-SiNx多层膜结构中纳米硅成核,以及从球形到鼓形的生长过程进行了研究. 建立了限制性晶化理论模型:在纳米硅生长过程中,由于界面能增大将导致生长停止,给出限制性晶化条件——a-Si:H子层厚度小于34 nm. 在激光晶化和常规热退火两种方法形成的a-SiNx/nc-Si/a-SiNx三明治结构和nc-Si/a-SiNx多层膜结构中验证了该理论模型.
关键词:
非晶硅
纳米硅
激光辐照
结晶 相似文献
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在等离子体增强化学气相淀积系统中,采用aSi:H层淀积和原位等离子体氧化相结合的逐层生长技术制备了aSi:H/SiO_2多层膜.在激光诱导限制结晶原理基础上,使用KrF准分子脉冲激光为辐照源,对aSi:H/SiO_2多层膜进行辐照,使纳米级厚度的aSi:H子层晶化.Raman散射谱和电子衍射谱的结果表明,经过激光辐照后纳米Si颗粒在原始的aSi:H子层内形成,晶粒尺寸可以根据aSi:H层的厚度精确控制.还研究了样品的光致发光(PL)特性以及激光辐照能量密度对PL性质的影响.
关键词:
脉冲激光
多层膜
限制结晶 相似文献
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a-Si/SiO2多量子阱材料制备及其晶化和发光 总被引:3,自引:0,他引:3
本文研究用等离子体增强化学气相淀积(PECVD)方法淀积SiO2和非晶硅(a-Si)时淀积速率和薄膜折射率与淀积条件的关系。选择合适的淀积条件制备了a-Si/SiO2多量子阱结构材料。用激光扫描退火方法使其晶化,当a-Si和SiO2层厚度分别为4nm和6nm时,形成了颗粒大小为3.8nm的硅晶粒。晶化后的样品在10K下可以观察到较强的光荧光发射,三个峰值波长分别为810、825和845nm. 相似文献
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L. Y. Zhu X. F. Huang W. B. Fan X. W. Wang W. Li L. Wang K. J. Chen 《Superlattices and Microstructures》2002,31(6):285
We employed atomic force microscopy, cross-section transmission electron microscopy and high-resolution electron microscopy to investigate the microstructures and surface morphology of laser interference crystallized a-Si : H/a-SiNx : H superlattices. The experimental results show that Si nanocrystallites (nc-Si) are formed within the initial a-Si : H sublayers and are patterned in certain regions with the same periodicity of 2.0 μ m as the phase-shifting mask grating. The size of nc-Si is limited by adjacent a-SiN x: H sublayers due to the constrained crystallization effect so it is possible to use this crystallization method to get a three-dimensional ordered nc-Si array. 相似文献
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A new method of phase-modulated excimer laser crystallization is adopted to fabricate the patterned nanometer-sized crystalline silicon (nc-Si) dots within the sandwiched structure (a-SiNx:H/a-Si:H/a-SiNx:H) films. The results of transmission electron microscopy, electron diffraction and Raman scattering show the ultra-thin and single-layer nc-Si films were patterned in the lateral direction and the size of crystallites is controlled by the thickness of as-deposited a-Si film in the longitudinal direction. The effects of the laser energy density on the structures of the samples and the crystallization mechanism are discussed. 相似文献
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L. Wang X. Huang Z. Ma Z. Li J. Shi L. Zhang Y. Bao X. Wang W. Li J. Xu K. Chen 《Applied Physics A: Materials Science & Processing》2002,74(6):783-786
The crystallinity of Si/SiNx multilayers annealed by a rapid thermal process and furnace annealing is investigated by a Raman-scattering technique and
transmission electron microscopy. It is found that the crystallization temperature varies from 900 °C to 1000 °C when the
thickness of a-Si:H decreases from 4.0 nm to 2.0 nm. Raman measurements imply that the high crystallization temperature for
the a-Si:H sublayers originates from the confinement modulated by the interfaces between a-Si:H and a-SiNx:H. In addition to the annealing temperature, the thermal process also plays an important role in crystallization of a-Si
sublayers. The a-Si:H sublayers thinner than 4.0 nm can not be crystallized by furnace annealing for 30 min, even when the
annealing temperature is as high as 1000 °C. In contrast, rapid thermal annealing is advantageous for nucleation and crystallization.
The origin of process-dependent crystallization in constrained a-Si:H is briefly discussed.
Received: 11 April 2001 / Accepted: 20 June 2001 / Published online: 30 August 2001 相似文献
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Sandwiched structures (a-SiNx/a-Si/a-SiNx) have been fabricated by the plasma enhanced chemical vapour deposition technique. A Si nanocrystal (nc-Si) layer was formed by crystallization of an a-Si layer according to the constrained crystallization principle after quasi-static thermal annealing at 1100℃ for 30 min. Transmission electron microscopy (TEM) and Raman scattering spectroscopy clearly demonstrated that nc-Si grains were formed in the as-deposited a-Si layer after annealing. The density of nc-Si grains is about 1011cm-2 as shown by TEM photographs. Using capacitance-voltage (C-V) measurements we investigated the electrical characteristics of the sandwiched structures. The charge storage phenomenon of the nc-Si layer was observed from the shift of flat-band voltage (VFB) in C-V curves at a high frequency (1 MHz). We estimated the density of nc-Si grains to be about 1011cm-2 from the shift value of VFB, which is in agreement with the result of TEM photographs. At the same time, we found that the shift of VFB increased with the increase of the applied constant dc voltage or the thickness of the nc-Si layer. 相似文献