硫化锌基底8～12μm红外增透膜的研究

为了提高硫化锌基底的透过率和膜层的机械强度,对硫化锌基底上的红外宽带减反射膜的设计和制备工艺进行了研究.经过实验,选取镀膜材料,优化沉积工艺参数以及采用离子束辅助沉积技术,研制出膜层附着力好.光学性能稳定的红外增透膜.最后,对制备的增透膜进行环境实验,各项指标均满足设计要求.     

含控制孔切槽爆破的裂隙扩展机制研究

为了丰富切槽爆破增透理论,以期为指导切槽爆破增透实践提供理论依据,采用理论分析、数值模拟、相似模拟试验的方法对切槽爆破在含控制孔情况下的裂隙扩展机制进行研究。研究表明:控制孔作用下的切槽爆破在切槽根部会产生抑制区,切槽方向上的压应变峰值是切槽45°方向上的压应变峰值的2.77倍,是拉应变峰值的1.94倍;应力波传播至控制孔后反射成拉伸波,反射拉伸波和切槽尖端的集中应力产生叠加,促进切槽尖端裂隙的扩展。说明含控制孔的切槽爆破可以有效避免爆破裂隙的随机发育,对爆破裂隙有着良好的控制导向作用,可达到定向爆破煤岩体的效果。     

Lithography-Free Fabrication of Large Area Subwavelength Antireflection Structures Using Thermally Dewetted Pt/Pd Alloy Etch Mask

We have demonstrated lithography-free, simple, and large area fabrication method for subwavelength antireflection structures (SAS) to achieve low reflectance of silicon (Si) surface. Thin film of Pt/Pd alloy on a Si substrate is melted and agglomerated into hemispheric nanodots by thermal dewetting process, and the array of the nanodots is used as etch mask for reactive ion etching (RIE) to form SAS on the Si surface. Two critical parameters, the temperature of thermal dewetting processes and the duration of RIE, have been experimentally studied to achieve very low reflectance from SAS. All the SAS have well-tapered shapes that the refractive index may be changed continuously and monotonously in the direction of incident light. In the wavelength range from 350 to 1800 nm, the measured reflectance of the fabricated SAS averages out to 5%. Especially in the wavelength range from 550 to 650 nm, which falls within visible light, the measured reflectance is under 0.01%.     

Ag颗粒表面等离子体增强GaAs太阳电池双层减反射膜的设计与模拟

Surface plasmon enhanced antireflection coatings for GaAs solar cells have been designed theoretically.The reflectance of double-layer antireflection coatings（ARCs） with different suspensions of Ag particles is calcu-lated as a function of the wavelength according to the optical interference matrix and the Mie theory.The mean dielectric concept was adopted in the simulations.A significant reduction of reflectance in the spectral region from 300 to 400 nm was found to be beneficial for the design of ARCs.A new SiO2/Ag-ZnS double-layer coating with better antireflection ability can be achieved if the particle volume fraction in ZnS is 1%-2%.     

梯度折射率宽带减反射光伏玻璃研究

采用二次腐蚀法制备了梯度折射率减反射光伏玻璃。SEM分析表明,多孔减反射层的微结构尺度在20～30nm左右,膜层厚度为100～300nm。通过计算模拟,确定了膜层折射率分布形式为Gaussian-like型。制备的梯度折射率减反射光伏玻璃透过率>96%的带宽超过了1200nm;在390～1022nm波段的透过率>99%;在350～1084nm的双面反射率<1%,其中624～922nm的双面反射率低于0.2%。     

干燥方式对SiO2/TiO2减反膜性能的影响

用溶胶-凝胶法在清洁的K9玻璃表面成功制备了均匀透明的纳米SiO2/TiO2复合减反射薄膜。分别采用远红外干燥、真空干燥、冷冻干燥、微波干燥等不同的干燥方式和不同干燥时间对同一薄膜进行热处理,系统地研究了不同干燥方式、温度、时间对薄膜的粗糙度、表面形貌及透射率的影响。结果表明,薄膜的最佳干燥条件为真空干燥箱160℃,干燥10h。     

膜厚对导电氧化锌宽带抗反射涂层的太赫兹传输影响

利用直流磁控溅射方法,在石英基底上制备了可用于太赫兹电磁波频率范围内的宽带抗反射涂层的掺铝氧化锌导电薄膜。在太赫兹时域光谱频率0.1~1.0THz范围内研究不同厚度的氧化锌薄膜的介电响应,得到了与频率相关的电导率、吸收和薄膜折射率,着重研究了膜厚对太赫兹波传输特性的调制作用。实验结果很好地符合了经典的Drude模型,表明可以通过控制氧化锌薄膜的厚度来改变太赫兹波的传输特性,并且导电氧化锌薄膜能够作为太赫兹频段范围的宽带抗反射涂层应用于衬底和光学器件上。     

发光二极管表面结构对出光特性的影响

用传输矩阵法模拟计算了AlGaInP发光二极管(LED)不同表面结构的光学特性,用等离子体增强化学气相沉积(PECVD)或磁控溅射掺铟氧化锡(ITO)设备,在带有DBR结构的外延衬底上制备出具有不同表面层结构的LED.通过实验结果对比表明,表面生长λ/4n SiON加λ2n ITO增透膜结构复合增透膜的LED,器件光学性能提高最佳,在20 mA注入电流下,光强和光通量分别达到141.7 mcd和0.4733 lm.比同样结构的无增透膜LED轴向光强和光通量分别提高138%和91%.     

Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure

In this work, Au-Bi₂Te₃ nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus) forewing (T_FW) as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi₂Te₃ nanocomposite thermoelectric film was analyzed by X-ray diffraction (XRD), field-emission scanning-electron microscopy (FESEM), and transmission electron microscopy (TEM). Coupled the plasmon resonances of the Au nanoparticles with the hierarchical sub-micron antireflection quasi-periodic structure, the Au-Bi₂Te₃ nanocomposite thermoelectric film possesses an effective infrared absorption and infrared photothermal conversion performance. Based on the finite difference time domain method and the Joule effect, the heat generation and the heat source density distribution of the Au-Bi₂Te₃ nanocomposite thermoelectric film were studied. The heterogeneity of heat source density distribution of the Au-Bi₂Te₃ nanocomposite thermoelectric film opens up a novel promising technique for generating thermoelectric power under illumination.