共查询到20条相似文献,搜索用时 93 毫秒
1.
2.
3.
4.
5.
本文利用扫描电子显微镜(SEM)和高分辨透射电子显微镜(HRTEM)研究了固溶处理和时效处理过程中铝硅二元合金中硅颗粒、析出相及硅颗粒与铝基体界面处的微观结构变化特征。研究结果表明:随着固溶时间的延长,硅颗粒的形态由树枝状逐渐变成椭球状和球状;时效过程中,溶入α-Al基体中的硅原子会在铝基体中聚集,形核并形成沿铝基体{111}面生长的硅析出相,同时还会在硅颗粒上析出一层硅的纳米孪晶,这些纳米孪晶会随着时效时间的延长不断长大。硅的孪晶壳层中存在大量孪晶和其他缺陷,除了常见的SiΣ3(111)孪晶外,观察到的孪晶类型还包括多重孪晶,如五重孪晶。 相似文献
6.
高剂量离子注入直接形成Ge纳米晶的物理机理 总被引:1,自引:1,他引:0
研究了单束双能高剂量Ge离子注入、不经过退火在非晶态SiO2薄膜中直接形成镶嵌结构Ge纳米晶的物理机制.实验中利用不加磁分析器的离子注入机,采用Ge弧光放电离化自动形成的Ge+和Ge2+双电荷离子并存的单束双能离子注入方法,制备了1e16~1e18cm-2多种剂量Ge离子注入的Si基SiO2薄膜样品.用GIXRD表征了Ge纳米晶的存在,并仔细分析得到了纳米晶形成的阈值剂量.通过TEM分析了Ge纳米晶的深度分布和晶粒尺寸.用SRIM程序分别计算了双能离子在SiO2非晶层的射程和深度分布,与实验结合,得到纳米晶形成的物理机制,即纳米晶的形成与单束双能离子注入时Ge+和Ge2+相互碰撞产生的能量沉积在SiO2中形成的局域高温有关. 相似文献
7.
采用 PECVD技术在 P型硅衬底上制备了 a- Si Ox∶ H/a- Si Oy∶ H多层薄膜 ,利用 AES和 TEM技术研究了这种薄膜微结构的退火行为 .结果表明 :a- Si Ox∶ H/a- Si Oy∶ H多层薄膜经退火处理形成 nc- Si/Si O2 多层量子点复合膜 ,膜层具有清晰完整的结构界面 .纳米硅嵌埋颗粒呈多晶结构 ,颗粒大小随退火温度升高而增大 .在一定的实验条件下 ,样品在 650℃下退火可形成尺寸大小合适的纳米硅颗粒 .初步分析了这种多层复合膜形成的机理 相似文献
8.
9.
CuS纳米掺杂聚合物光伏器件中的电荷传输 总被引:1,自引:0,他引:1
制备了CuS纳米颗粒掺杂聚合物MEH-PPV的光伏器件.研究了3种MEH-PPV/CuS掺杂比例(1∶1.00、1∶1.25、1∶2.50)光伏器件的光电流响应谱与动态双脉冲光电流响应,结果表明:CuS良好的导电性可以改善器件中的载流子传输,从而提高光电流响应值;在较低的CuS纳米颗粒掺杂浓度下,MEH-PPV与CuS纳米颗粒间形成的界面有可能造成电荷积累,会直接影响到光电流响应值;在CuS纳米颗粒掺杂浓度较高时,电荷积累现象基本消失,这是因为高浓度时形成的聚集相改善了两种载流子的传输,抑制了MEH-PPV/CuS界面的电荷积累. 相似文献
10.
11.
M. Hamasaki 《Solid-state electronics》1982,25(3):205-211
A simple model to account for the generation kinetics of oxide charges and surface states during oxidation of silicon is presented. In the model, oxide charges and surface states are generated by a reaction between silicon and oxygen within the mono-molecular layer of the Si/SiO2 interface and are thermally annealed independently of this reaction. A two step oxidation technique was used to investigate the electronic structure of the Si/SiO2 interface and it was found that centers of fast surface states are located within 1.4–2.0 Å of the interface and that the centroid of oxide charges is located at about 8 Å from the interface. These results agreed with the model. 相似文献
12.
对含 F MOS结构的抗电离辐射特性和机理进行了系统研究。其结果表明 :F减少工艺过程引入栅介质的 E’中心缺陷和补偿 Si/ Si O2 界面 Si悬挂键的作用 ,将导致初始氧化物电荷和界面态密度的下降 ;栅 Si O2 中的 F主要以 F离子和 Si- F结键的方式存在 ;含 F栅介质中部分 Si- F键替换 Si- O应力键而使 Si/ Si O2 界面应力得到释放 ,以及用较高键能的 Si- F键替换 Si- H弱键的有益作用是栅介质辐射敏感性降低的根本原因 ;含 F CMOS电路辐射感生漏电流得到抑制的主要原因是场氧介质中氧化物电荷的增长受到了明显抑制。 相似文献
13.
激光脉冲频率对纳米Si晶薄膜形貌的影响 总被引:5,自引:5,他引:5
在气压为10 Pa的惰性气体Ar环境下,采用XeCl准分子激光器(波长308 nm),调整激光单脉冲能量密度为4 J/cm2,激光烧蚀电阻率为3000Ω.cm的高纯单晶Si靶,在玻璃或Si衬底上沉积制备了纳米Si晶薄膜。实验中靶和衬底间距离保持为3 cm,对衬底既没有加温也没有冷却。拉曼(Raman)谱测量结果表明,所制备的薄膜中已有纳米Si晶粒形成。保持脉冲总数不变,分别取激光脉冲频率为1 Hz,3 Hz,10 Hz和20 Hz,相应沉积时间约为10 min,3.3 min,1 min和0.5 min,采用扫描电子显微镜(SEM)观察所得样品的表面形貌,不同脉冲频率下的结果比较显示,脉冲频率越大,制备的纳米Si晶薄膜的平均晶粒尺寸就越小,晶粒尺寸分布也越均匀。沉积动力学过程的非线性是导致实验出现该结果的原因。 相似文献
14.
采用激光烧蚀法和电化学腐蚀法制备硅纳米颗粒,两种方法制备的硅纳米颗粒粒径与形貌都不同,而且紫外-可见吸收谱也有很大差别.分析紫外-可见吸收谱发现,硅纳米颗粒与单晶硅相比发生了能带展宽、吸收边蓝移现象,并且有直接能隙的特点;两种方法制备的硅纳米颗粒的光致发光都与硅颗粒的粒径分布和表面层成分密切相关,并且光致发光谱还随激发波长的变化而规律地改变.用量子限制和表面层成分结合模型分析解释了这些现象. 相似文献
15.
16.
17.
In this study, we describe the transport of gold (Au) nanoparticles from the surface into crystalline silicon (Si) covered by silicon oxide (SiO(2)) as revealed by in situ high-resolution transmission electron microscopy. Complete crystalline Au nanoparticles sink through the SiO(2) layer into the Si substrate when high-dose electron irradiation is applied and temperature is raised above 150 degrees C. Above temperatures of 250 degrees C, the Au nanoparticles finally dissolve into fragments accompanied by crystallization of the amorphized Si substrate around these fragments. The transport process is explained by a wetting process followed by Stokes motion. Modelling this process yields boundaries for the interface energies involved. 相似文献
18.
Yong‐Bing Tang Xiang‐Hui Bo Chun‐Sing Lee Hong‐Tao Cong Hui‐Ming Cheng Zhen‐Hua Chen Wen‐Jun Zhang Igor Bello Shuit‐Tong Lee 《Advanced functional materials》2008,18(21):3515-3522
A new catalyst seeding method is presented, in which aerosolized catalyst nanoparticles are continuously self‐assembled onto amine‐terminated silicon substrates in gas phase to realize controllable synthesis of vertically aligned Mg‐doped GaN nanorod arrays on n‐type Si (111) substrates. The diameter, areal density, and length of GaN nanorods can be controlled by adjusting the size of Au nanoparticles, flowing time of Au nanoparticles, and growth time, respectively. Based on the synthesis of p‐type GaN nanorods on n‐type Si substrates, p‐GaN nanorod/n‐Si heterojunction diodes are fabricated, which exhibit well‐defined rectifying behavior with a low turn‐on voltage of ~1.0 V and a low leakage current even at a reverse bias up to 10 V. The controllable growth of GaN nanorod arrays and the realization of p‐type GaN nanorod/n‐type Si heterojunction diodes open up opportunities for low‐cost and high‐performance optoelectronic devices based on these nanostructured arrays. 相似文献
19.
Tristan L. Temple Darren M. Bagnall 《Progress in Photovoltaics: Research and Applications》2013,21(4):600-611
Metal nanoparticles offer the possibility of improved light trapping in solar cells, but careful design is required to maximise scattering and minimise parasitic absorption across the wavelength range of interest. We present an analysis of the broadband scattering and absorption characteristics of spherical metal nanoparticles, optimized for either crystalline silicon (c‐Si) or amorphous silicon (a‐Si:H) solar cells. A random two‐dimensional array of optimally sized Ag spheres can scatter over 97% of the AM1.5 spectrum from 400 to 1100 nm. Larger particles are required for c‐Si devices than a‐Si:H due to the increased spectral range, with optimum particle sizes ranging from 60 nm for a‐Si:H to 116 nm for c‐Si. Positioning the particles at the rear of the solar cell decreases absorption losses because these principally occur at short wavelengths. Increasing the refractive index of the surrounding medium beyond the optimum value, which is 1.0 for a‐Si:H and 1.6 for c‐Si, shifts absorption to longer wavelengths and decreases scattering at short wavelengths. Ag nanoparticles scatter more of the solar spectrum than Au, Cu or Al nanoparticles. Of these other metals, Al can only be considered for a‐Si:H applications due to high absorption in the near‐infrared, whereas Au and Cu can only be considered for the rear of c‐Si devices due to high absorption in the ultraviolet (UV) and visible. In general, we demonstrate the importance of considering the broadband optical properties of metal nanoparticles for photovoltaic applications. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
20.
M. Hamasaki 《Solid-state electronics》1982,25(6):479-486
The oxidation kinetics of silicon is investigated using two-step oxidation in dry O2. It is found that in an initial state of second oxidation the growth rate of the oxide is different from the oxide's equilibrium growth rate and that the difference in these growth rates is due to the difference in the linear growth rates in these two stages. To explain the difference in the growth rates at the two stages, a model which accounts for the effect of oxide charges on the kinetics of the oxidation of Si is presented. In this model, negatively-charged oxidant species are prevented from reaching the Si/SiO2 interface by the oxide field near the interface caused by the positive charges generated by the oxidation. 相似文献