<i>γ</i>-Ray Irradiation Effect on MCF Rubber Solar Cells with both Photovoltaics and Sensing Involving Semiconductors Fabricated under Magnetic and Electric Fields

For cases in which a robot with installed solar cells and a sensor operates in a nuclear reactor building or in space for extravehicular activity, we require elastic and extensible solar cells. More than two different types of sensing are also required, minimally with photovoltaics and built-in electricity. Magnetic compound fluid (MCF) rubber solar cells are made of rubber, so they are elastic and extensible as well as sensitive. To achieve flexibility and an effective photovoltaic effect, MCF rubber solar cells must include both soluble and insoluble rubbers, Fe3O4, TiO2, Na2WO4∙2H2O, etc. On the basis of this constitution, we propose a consummate fabrication process for MCF rubber solar cells. The characteristics of these cells result from the semiconductor-like role of the molecules of TiO2, Fe3O4, Ni, Na2WO4∙2H2O, polydimethylsiloxane (PDMS), natural rubber (NR), oleic acid, polyvinyl alcohol (PVA), water and magnetic cluster involved in the MCF rubber. Their tendencies can be deduced by synthesizing knowledge about the enhancement of the reverse-bias saturation current IS and the diode ideality factor N, with conventional knowledge about the semiconductor affected by γ-irradiation and the attenuation of the photon energy of γ-rays.

Preparation and characterization of iron-ore-imbedded silicone rubber materials for radiation protection

Iron-ore-imbedded silicone rubber materials were produced for radiation shielding. Samples were tested against a Co-60 gamma source, which is widely used in nuclear technology and medicine. Decreasing the particle size of iron ore resulted in better gamma radiation protection owing to more homogenous distribution. In addition, the materials had flexible properties up to the addition of 60 wt% iron ore content. Further, 0.5 mm Pb E gamma protection was provided by using 2.06-mm-thick SDT-60 as the Co-60 source. Iron ore–silicone rubber composites are candidate materials for lead-free flexible radiation protection systems owing to their relatively inexpensive and easy production.

EFFECTS OF SOME PHENYLETHYNYLSILICON COMPOUNDS ON HEAT-CURABLE SILICONE RUBBER Ⅲ 1, 1, 3, 3-TETRAMETHYL-1, 3-DIPHENYLETHYNYL-DISILOXANE

We have shown that some phenylethynylsilicon compounds are good cure crosslinkersof heat-curable silicone rubber(HCSR). In this paper the effects of 1, 1, 3, 3-tetramethyl-1, 3-diphenylethynyldisiloxane (TMDPDS) as a crosslinker on HCSR were studied. Thevulcanizates with fine mechanical properties could be obtained with suitable amounts ofTMDPDS. Sol fractions, and crosslinking density of vulcanizates and vulcanizationretardation effect of TMDPDS on hydrosilation curing silicone rubber were also discussed.

Total Ionizing Dose Radiation Effects in the P-Type Polycrystalline Silicon Thin Film Transistors

The total ionizing dose radiation effects in the polycrystalline silicon thin film transistors are studied. Transfer characteristics, high-frequency capacitance-voltage curves and low-frequency noises (LFN) are measured before and after radiation. The experimental results show that threshold voltage and hole-field-effect mobility decrease, while sub-threshold swing and low-frequency noise increase with the increase of the total dose. The contributions of radiation induced interface states and oxide trapped charges to the shift of threshold voltage are also estimated. Furthermore, spatial distributions of oxide trapped charges before and after radiation are extracted based on the LFN measurements.

High energy electron radiation effect on Ni and Ti/4H-SiC Schottky barrier diodes at room temperature

This paper reports that Ni and Ti/4H-SiC Schottky barrier diodes （SBDs） were fabricated and irradiated with 1 MeV electrons up to a dose of 3.43 × 10^14 e/cm2. After radiation, the Schottky barrier height φB of the Ni/4H-SiC SBD increased from 1.20 eV to 1.21 eV, but decreased from 0.95 eV to 0.94 eV for the Ti/4H-SiC SBD. The degradation of φB could be explained by interface states of changed Schottky contacts. The on-state resistance Rs of both diodes increased with the dose, which can be ascribed to the radiation defects. The reverse current of the Ni/4H-SiC SBD slightly increased, but for the Ti/4H-SiC SBD it basically remained the same. At room temperature, φB of the diodes recovered completely after one week, and the RS partly recovered.

Supergiant Barocaloric Effects in Acetoxy Silicone Rubber over a Wide Temperature Range:Great Potential for Solid-state Cooling

Solid-state cooling based on caloric effects is considered a viable alternative to replace the conventional vapor-compression refrigeration systems.Regarding barocaloric materials,recent results show that elastomers are promising candidates for cooling applications around room-temperature.In the present paper,we report supergiant barocaloric effects observed in acetoxy silicone rubber—a very popular,low-cost and environmentally friendly elastomer.Huge values of adiabatic temperature change and reversible isothermal entropy change were obtained upon moderate applied pressures and relatively low strains.These huge barocaloric changes are associated both to the polymer chain rearrangements induced by confined compression and to the first-order structural transition.The results are comparable to the best barocaloric materials reported so far,opening encouraging prospects for the application of elastomers in near future solid-state cooling devices.

Epoxy-POSS/silicone rubber nanocomposites with excellent thermal stability and radiation resistance

Due to the rigid Si-O-Si backbone,silicone rubber(SR)have a widespread application in extreme environment such as high temperature and high-level radiation.However,the radiation stability of SR still does not meet the practical needs in special radiation environments.Herein we prepared epoxy POSS(e POSS)/SR nanocomposites with excellent thermal stability and radiation resistance.As a physical crosslinking point in the SR,addition of small amount of ePOSS not only enhanced the mechanical properties of the matrix,but also improved its thermal stability greatly due to their good compatibility.e POSS/SR had higher radiation stability in air than SR owing to the inhibition of radiation oxidation by ePOSS,and the yield of main gaseous radiolysis products(CH_(4),H_(2),CO and CO_(2))of SR and ePOSS/SR nanocomposites was determined.By analyzing the changes of chemical structure,thermal properties and mechanical properties of the ePOSS/SR nanocomposite,combined with the characteristics of gas products afterγ-irradiation,the radiation induced crosslinking and degradation mechanism of the nanocomposites was proposed comprehensively.

Neutron radiation effect on 4H-SiC MESFETs and SBDs

4H-SiC metal Schottky field effect transistors（MESFETs） and Schottky barrier diodes（SBDs） were irradiated at room temperature with 1 MeV neutrons.The highest neutron flux and gamma-ray total dose were 1×1015 n/cm2 and 3.3 Mrad（Si）,respectively.After a neutron flux of 1×1013 n/cm2,the current characteristics of the MES-FET had only slightly changed,and the Schottky contacts of the gate contacts and the Ni,Ti/4H-SiC SBDs showed no obvious degradation.To further increase the neutron flux,the drain current of the SiC MESFET decreased and the threshold voltage increased.φB of the Schottky gate contact decreased when the neutron flux was more than or equal to 2.5×1014 n/cm2.SiC Schottky interface damage and radiation defects in the bulk material are mainly mechanisms for performance degradation of the experiment devices,and a high doping concentration of the active region will improve the neutron radiation tolerance.

硅橡胶辐射老化理论模拟研究进展

硅橡胶由于具有良好的弹性、热稳定性、耐高低温性和耐老化性能,被广泛用于电离辐射环境中服役的高端装备上。由于其辐射老化行为和机理异常复杂,目前的研究方法实验技术和理论计算并重。本文简要综述了硅橡胶辐射老化模拟研究进展,从多尺度理论计算视角梳理了相关研究对解决具体问题的计算思路,并与实验表征结果互相补充印证。依据计算模拟理论方法的时空尺度特征,可分为量子电动力学、密度泛函理论、量子分子动力学、反应分子动力学、分子动力学、本构模型与有限元方法。这些计算模拟方法与材料和辐射相互作用过程及机制、体系损伤演化规律及机理、结构性能关系的研究需求密切相关。部分研究工作涉及多个尺度的模拟计算,依据其主要特色总结写入上述几个模拟方法分类板块。本文描绘了硅橡胶辐射老化模拟的阶段全景图,概述了相关研究现状以及学界和工程界面临的挑战,有望为相关实验研究和工程问题的解决提供新的思路和认识基础。

SOI高压LDMOS器件氧化层抗总电离剂量辐射效应研究

绝缘体上硅(SOI)高压横向扩散金属氧化物半导体(LDMOS)器件是高压集成电路的核心器件,对其进行了总电离剂量(TID)辐射效应研究。利用仿真软件研究了器件栅氧化层、场氧化层和埋氧化层辐射陷阱电荷对电场和载流子分布的调制作用,栅氧化层辐射陷阱电荷主要作用于器件沟道区,而场氧化层和埋氧化层辐射陷阱电荷则主要作用于器件漂移区;辐射陷阱电荷在器件内部感生出的镜像电荷改变了器件原有的电场和载流子分布,从而导致器件阈值电压、击穿电压和导通电阻等参数的退化。对80 V SOI高压LDMOS器件进行了总电离剂量辐射实验,结果表明在ON态和OFF态下随着辐射剂量的增加器件性能逐步衰退,当累积辐射剂量为200 krad(Si)时,器件的击穿电压大于80 V,阈值电压漂移为0.3 V,器件抗总电离剂量辐射能力大于200 krad(Si)。

改性球形氧化铝/褶皱结构石墨烯导热硅橡胶的制备及性能

面对5G时代,高功率化、集成化设备器件的热管理已成为影响性能的关键因素,热管理技术的飞速发展对导热界面材料的柔软性、绝缘性、导热性及可靠性等提出了更高的需求。以二维片状石墨烯(GNP)和不同粒径的球形氧化铝(Al_(2)O_(3))为导热填料,对其进行改性以改善填料在硅橡胶基体中的分散性,增强界面间结合,减少界面热阻。然后采用热压原位固化工艺,利用球形Al_(2)O_(3)将各向异性的GNP形成褶皱结构,制备了改性球形Al_(2)O_(3)/褶皱结构石墨烯导热硅橡胶复合材料。探讨了导热填料的含量、复合材料样品厚度等对导热硅橡胶复合材料综合性能的影响。结果表明,当复合材料样品厚度为0.8 mm,GNP质量分数为8%,Al_(2)O_(3)质量分数为50%时,复合材料面内热导率可达12.058 W/(m·K),面外热导率可达5.097 W/(m·K)。复合材料具有较好的柔性,添加GNP和Al_(2)O_(3)后,断裂伸长率均超过120%,最高可达171.68%。另外,在GNP质量分数为5%,Al_(2)O_(3)质量分数为50%时,当调节复合材料厚度为2 mm时,其击穿电压能够达到3.5 kV,满足一定的绝缘性能要求;此时面内热导率为1.979 W/(m·K),面外热导率为1.231W/(m·K)。与传统共混浇铸制备的硅橡胶片相比,该策略能够形成互联导热网络以获得高导热性能硅橡胶片,在大功率电子器件领域具有巨大的应用前景。

动态流变行为在三元乙丙橡胶/硅橡胶共混物形态结构研究中的应用

利用开放式炼胶机制备了三元乙丙橡胶(EPDM)与硅橡胶(SR)混炼胶和单相硫化硅橡胶(v-SR)的共混胶,通过流变行为研究了组成比例、界面交联作用等对共混体系形态结构的影响,并采用扫描电子显微镜和两相剥离强度对形态结构的研究结果进行了验证。结果表明,动态流变行为成功预测了高黏度聚合物复合体系的形态结构。共混物中EPDM的用量在30~70份(质量,下同)时,EPDM/SR混炼胶的形态呈双相连续结构。用超过1份的过氧化物交联剂对EPDM用量为70份的EPDM/SR混炼胶中的SR进行单相交联,v-SR的连续结构发生了融合,转变成颗粒状结构,且颗粒结构的相畴随着交联剂用量的增加而增大,而高剂量的交联剂可以使两相形成共交联。

SiC MOSFET的质子单粒子效应

SiC金属氧化物半导体场效应晶体管(MOSFET)在深空探测领域具有广阔的应用前景,但空间质子引发的单粒子效应(SEE)对航天器稳定运行造成了严重威胁。对平面栅结构与非对称沟槽栅结构的SiC MOSFET进行了能量为70、100与200 MeV的质子辐照实验。实验结果表明,两种SiC MOSFET的单粒子烧毁(SEB)阈值电压均大于额定漏源电压的75%;SEB阈值电压随质子能量升高而降低。对两种器件进行辐照后栅应力测试发现,两种结构的器件由于沟道不同而对栅应力的响应存在差异;不同的质子能量会在栅极引入不同程度的辐射损伤,低能质子更容易在栅氧化层发生碰撞而引入氧化物潜在损伤。该研究可为揭示SiC MOSFET质子SEE机理和评估抗辐射能力提供参考。

镀镍石墨导电硅橡胶电磁屏蔽复合材料的制备及性能

为了改善常规方法难以兼顾电磁屏蔽橡胶高导电导磁性能和其力学性能,以镀镍石墨(NCG)为填料,偶联剂为改性剂,硅橡胶为基材,采用机械共混的方式制备了系列镀镍石墨导电硅橡胶电磁屏蔽复合材料。测试分析了电磁屏蔽橡胶的硫化特性、力学性能、导电性能和屏蔽效能,并使用扫描电子显微镜表征了电磁屏蔽橡胶的微观组织。研究了镀镍石墨(NCG)添加量对导电硅橡胶力学性能、导电性能和屏蔽效能的影响,并对电磁屏蔽橡胶的导电和屏蔽机理进行了分析。结果表明:当填料添加量为180份时,填料能够在基体内部形成完整稳定的三维导电网络,使复合材料在具有良好力学性能的同时还具有优异的电学性能,电磁屏蔽橡胶的拉伸强度为3.688MPa,体积电阻率为0.24Ω·cm,其在X波段(8.2~12.4GHz)内的平均屏蔽效能可达到55.25dB。

硅基光电探测器空间辐射效应研究进展

硅基光电子技术结合了高集成度的大规模集成电路制造技术与光电子芯片的大带宽、高速率等优势,推动硅基光电器件在高能物理实验、医学影像和高能粒子碰撞器等领域的广泛应用。然而,应用于空间环境和医疗探测器的光电探测器在运行周期中预计会受到~10^(12)particles/cm^(2)的累积注量,而应用于大型粒子对撞机的新型探测器则要经受~10^(14)particles/cm^(2)的辐射注量。本文详细阐述了硅基光电探测器的空间辐射效应研究现状,主要包括不同粒子辐照后硅基光电二极管、雪崩光电二极管、单光子探测器以及光电倍增管等主流光电探测器的辐射效应研究进展。研究结果表明,探测器抗电离总剂量性能较好,位移损伤是导致其关键性能参数退化的主要原因,由于工作原理差异,各类器件在辐射环境中表现出不同退化行为和作用机理。

Temperature Effects on the Electrical Performance of Large Area Multicrystalline Silicon Solar Cells Using the Current Shunt Measuring Technique

The temperature effects on the electrical performance of a large area multicrystalline silicon solar cell with back-contact technology have been studied in a desert area under ambient conditions using the current shunt measuring technique. Therefore, most of the problems encountered with traditional measuring techniques are avoided. The temperature dependency of the current shunt from 5oC up to 50oC has been investigated. Its temperature coefficient proves to be negligible which means that the temperature dependency of the solar cell is completely independent of the current shunt. The solar module installed in a tilted position at the optimum angle of the location, has been tested in two different seasons (winter and summer). The obtained solar cell short circuit current, open circuit voltage and output power are correlated with the measured incident radiation in both seasons and all results are discussed.

^(60)Co-γ射线辐射还原氧化石墨烯制备导热硅橡胶

将氧化石墨烯(GO)粉末配制成醇/水溶液,在^(60)Co-γ射线作用下进行还原,制备辐射还原GO。利用傅里叶变换红外光谱和X射线光电子能谱分析,研究了不同辐照剂量下,氧化石墨烯的含氧官能团变化情况、C/O原子比以及还原程度,确定了在120 kGy的辐照剂量下,氧化石墨烯的还原程度最高,C元素含量为88.69%,O元素含量为11.31%,C/O原子比达到7.84。以20 g甲基乙烯基聚硅氧烷为基胶,端含氢硅油为扩链剂、侧含氢硅油为交联剂,加入铂金催化剂、抑制剂,以球形氧化铝、辐射还原GO为导热填料,制备了高性能的导热硅橡胶。考察了氧化铝和GO的添加量对导热硅橡胶性能的影响。结果表明,在球形氧化铝添加量为基胶的300%的时候,导热硅橡胶具有最佳的拉伸强度和弹性;辐射还原后的GO,可大幅提升硅橡胶的热导率,并且与C/O原子比成正相关。当GO的C/O原子比为7.84,添加量为基胶的5%,氧化铝的添加量为基胶的300%时,导热硅橡胶的拉伸强度为0.82 MPa,热导率为5.18 W/(m·K),具有较好的综合性能。

航天飞行器用高发射率红外辐射涂层的制备及性能研究

以碱金属氢氧化物及其氧化物和SiC等复配得到了高发射率红外辐射粉料,然后与硅橡胶混合配置,再通过空气喷涂法制备得到了高发射率红外辐射涂层。通过力学、热学、红外辐射、隔热试验等对涂层的各项性能进行了表征。结果表明:辐射涂层具有高红外发射率(>0.85),表现出优异的隔热性能。与添加1 mm长的碳纤维制备的涂层相比,3种添加500μm的短切玻璃纤维制备的自研辐射涂层具有更好的力学性能、界面结合强度以及表面状态。综合对比3种自研辐射涂层,其中添加由SiC以及铁、铝、镁的氧化物组成的辐射填料制备的涂层A效果最优,红外发射率高达0.93,拉伸强度达到2.89 MPa,断裂伸长率达到114%,拉伸剪切强度达到1.36 MPa。

辐照交联无卤阻燃可陶瓷化硅橡胶复合材料的构建及性能研究

可陶瓷化硅橡胶复合材料作为一种新型的耐火材料,在电线电缆行业具有广阔的应用潜力。为了改善材料的力学强度和阻燃性能,本研究以甲基乙烯基硅橡胶(MVSR)为基体,构建三种组成不同的适用于辐照交联工艺的无卤阻燃可陶瓷化硅橡胶复合绝缘材料。研究发现,通过放射源^(60)Co(γ射线)对可陶瓷化硅橡胶复合材料进行辐照交联处理,能够极大提升复合材料的力学强度和模量。其中,基于烯丙基环三磷腈(CP-Allyl)和Mg(OH)_(2)复配阻燃剂的复合材料3样品具有相对好的辐照交联效果和阻燃性能。经过80 kGy剂量辐照的复合材料3样品的拉伸强度可达到4.65 MPa,其极限氧指数达34.4%。另外,复合材料在700~1000℃高温烧蚀之后,均能够形成致密、坚硬的陶瓷化层。可见,本研究所构建的辐照交联硅橡胶复合材料具有优良的性能和高温成瓷特性,有望在电线电缆用绝缘材料领域获得应用。

大量程高韧导电硅橡胶复合材料压力传感器的研制

基于纳米导电橡胶的压阻效应,使用基体材料硅橡胶、纳米超导电用炭黑、真丝纤维织物、叉指电极、缓冲高分子材料及封装模具,采用密炼、开炼、固化、封装等工艺制备了导电硅橡胶复合材料压力传感器,通过优化导电填料在硅橡胶基体中的含量制得了具有最佳压阻特性的导电硅橡胶复合材料,最后探究了封装压力传感器在桥梁支座模型上的应用性能。结果表明,当纳米超导电用炭黑BeaBlack CT-5质量分数为6.11%时,导电硅橡胶复合材料达到渗透阈值点,其压阻特性最佳;将真丝纤维织物植入导电硅橡胶所得的导电传感复合材料再与柔性叉指状单层电极进行结合并封装处理,可制备量程增大、探测灵敏、韧性增强的压力传感器;该压力传感器压力信号与电信号具有良好的线性关系,可以实现0~40 MPa范围内的压力探测;此外该压力传感器在桥梁支座模型测试中的测试值与理论值高度吻合。