铜辅助化学腐蚀条件对多孔硅的影响

以铜(Cu)作为催化剂,采用两步化学腐蚀法成功制 备了微纳米多孔硅(PS)。本文方法成本低廉、操 作简易。系统研究了腐蚀液中H₂O₂浓度、Si衬底掺杂浓度、腐蚀液温度和腐 蚀时间对PS表 面形貌和腐蚀深度的影响,并得到最佳制备参数。高、低掺Si衬底所采用的最佳配比腐蚀液 中的H₂O₂浓度分 别达到0.70mol/L和0.24mol/L。在 25℃腐蚀液中,腐蚀2h得到约200nm深的纳米级孔洞 ,其表面反射率在 宽波段内降低到5%以下;而在50℃腐蚀液中,经过2～ 4h的腐蚀,可得到14～41μm深的结构稳定的微纳 米级孔洞。文中还对Cu辅助腐蚀与其他金属辅助腐蚀(MACE)作了对比,分析了Cu辅助腐蚀获 得锥状孔洞的原因和机理。     

MACE法制备多孔硅的形貌及光致发光性能

采用金属辅助化学腐蚀(MACE)法,通过控制不同的腐蚀时间制备出多孔硅.利用扫描电子显微镜(SEM)观察多孔硅形貌,分析结果表明,随着腐蚀时间的增加,硅表面腐蚀孔洞变大,孔洞深度增加,同时孔洞深度的增加速率随之变缓.采用325 nm He-Cd激光光源的荧光光谱仪进行光致发光测试,研究在325 nm的激发光下不同腐蚀时...     

倒金字塔结构的黑硅PIN光电探测器的研究

由于晶体硅间接带隙的本质,光的吸收系数较低 ,影响了硅基光电探测器的量子效率。倒金字塔结构被证明是能够使得单晶硅片的光吸收效 率接近Yablonovitch limit的有效陷光结构。本论文采用金属催化腐蚀技术在单晶硅上制备具有随机分布的 倒金字塔陷光结构,并将其应用 到PIN光电探测器。结果显示具有倒金字塔结构的黑 硅PIN光电探测器加权平均反射率从20.18%降低至4.77%,探测器的漏电流仅0.9 nA, 光谱响应度达到0.64 A/W,较常规硅探测器提高33%。这些结果表明金属催化腐蚀技 术形成的倒金字塔结果能有效降低器件的表面反射率,从而提高探测器的光谱响应度。     

多晶黑硅表面微结构对电池效率的影响

采用Ag离子辅助化学刻蚀法制备了多晶黑硅薄片,使用NaOH溶液处理多晶黑硅表面,增大其表面纳米孔直径,使SiNx薄膜能够均匀覆盖整个黑硅表面,提高黑硅的钝化效果,进而提高多晶黑硅电池光电转化效率.通过反射谱仪、扫描电子显微镜(SEM)、太阳电池测试系统等测试和表征不同扩孔时间对多晶黑硅各方面性能的影响.结果表明:未被NaOH扩孔处理的多晶黑硅的反射率最低,为5.03％,多晶黑硅太阳电池的光电转化效率为16.51％.当多晶黑硅被NaOH腐蚀40 s时,反射率为10.01％,电池的效率为18.00％,比普通多晶硅太阳电池的效率高2.19％,比未被扩孔处理的多晶黑硅太阳电池的效率高1.49％.     

微孔阵列结构的纳秒激光制备及陷光性能研究

为了制备形状可控、有序阵列的陷光微结构表面,使用纳秒激光器在钛合金(Ti6Al4V)表面加工呈六角形分布的微孔阵列结构,研究了不同激光扫描次数对表面微孔阵列结构形貌和反射率的影响。研究结果表明,随着激光扫描次数的增加,微孔结构表面的反射率逐渐降低,当激光扫描次数增加至40次时,微米级孔洞的直径约为(68±5)μm,孔洞深度约为(175±5)μm,在400 nm～1 000 nm波长范围内微孔阵列结构表面的平均反射率降低至1.3%。纳秒激光制备的微孔阵列结构表面有效增强了钛合金表面的陷光性能,在光学隐身、屏蔽杂散光等领域内具有重要的应用前景。     

TiO_2/Ag/PAA纳米复合结构的制备及其光吸收性能

采用循环阳极氧化-腐蚀法制备了V型多孔阳极氧化铝(PAA)模板,在PAA上热蒸发沉积Ag薄膜后,再原子层沉积TiO_2薄膜,制备了TiO_2/Ag/PAA三维纳米复合结构。紫外-可见吸收光谱的结果表明,TiO_2/Ag/PAA复合结构在可见光区域的吸收率显著提高。当Ag薄膜沉积厚度为30 nm,TiO_2的原子层沉积厚度为20 nm时,所得TiO_2/Ag/PAA复合结构的吸收率为94.5%~99.0%。     

微构造硅表面形貌的陷光特性研究

在特定的气体氛围下,用一定能量密度的飞秒激光连续照射单晶硅片表面,可制备出表面具有准规则排列微米量级锥形尖峰结构的黑硅材料。利用几何光学中光的传输理论,研究了黑硅材料的陷光特性,以及黑硅表面准规则排列的微米量级锥形尖峰结构的形状和密度对反射次数的影响。获得黑硅的表面准规则排列的微米量级锥形尖峰结构的高度越高、间距越小和底角越大,它的陷光效果就越好的结论。     

湿法黑硅工艺中银残留对太阳电池性能的影响

采用银金属辅助化学腐蚀技术在多晶硅衬底上制备了黑硅绒面,通过能谱仪、扫描电子显微镜和反射率测试仪对所制备黑硅样品的表面银金属残留、形貌和光吸收进行了表征和分析。在此基础之上,通过扩散、腐蚀清洗、镀膜和印刷烧结测试等工序,将多晶黑硅样品制备成太阳电池片,并通过I-V和EL测试仪对其光伏性能和电致发光特性进行了测量和分析。结果表明,与无银残留样品规则、均匀的圆形腐蚀坑绒面相比,黑硅制备过程中如果有银离子残留在表面,扩孔后的表面形貌呈现为方向杂乱和深浅不一的凹坑状形貌,且凹坑周围边界尖锐、形状不规则,制备成电池后转换效率偏低3.03%。     

基于纳米胺结构保护层的多波段高反射Ag基膜系制备

Ag基膜系具有在可见到近红外波段最高的反射率,但Ag的环境稳定性较差,易受腐蚀而导致反射率降低。采用离子束辅助电子束蒸发沉积(IAD)方式制备了不同厚度比例的Ta₂O₅-SiO₂纳米胺薄膜,计算出有效折射率和膜层残余应力,选用Ta₂O₅厚度占比为75%的纳米胺薄膜,进一步设计制备了纳米胺结构保护层Ag基膜系和常规两层式结构保护层Ag基膜系,实现了多波段高反射率目标,并且两种Ag基膜系的残余应力相近。在24 h湿热实验后,纳米胺结构保护层Ag基膜系的反射率红移量小于常规两层式结构保护层Ag基膜系;在144 h湿热实验后,纳米胺结构保护层Ag基膜系表面缺陷腐蚀程度小于常规两层式结构保护层Ag基膜系,结合聚焦离子束制样后利用TEM观察结果,表明纳米胺结构保护层具有更高的致密度,能够为Ag基膜系提供更优良的环境稳定性。     

多孔硅负载银纳米颗粒提高硅基MSM光电探测器性能的研究

利用金属辅助刻蚀的方法在单晶硅片表面制备了多孔硅,结果表明多孔硅表面纳米结构的陷光作用在宽光谱范围内大幅提高了硅片的光吸收率。将银纳米颗粒负载到多孔硅表面,研究了其对硅基金属-半导体-金属型光电探测器(MSM-PDs)性能的影响。与基于硅片和多孔硅结构的MSM-PDs相比,基于多孔硅负载银纳米颗粒制备的MSM-PDs在420 nm入射光照射条件下的光暗电导比以及光响应度都有显著提高,这主要得益于表面纳米结构对暗电导的降低及光场中银纳米颗粒的LSPR效应对光电导的提升作用。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks