高温处理对镍诱导晶化硅上的薄膜晶体管性能的影响

采用标准双栅 CMOS工艺在镍诱导非晶硅横向晶化形成的多晶硅上制造了高性能的薄膜晶体管 ,并详细研究了器件制备前高温预处理对薄膜晶体管性能的影响 .实验发现不同的温度处理 ,将引起器件性能的显著变化 .在10 0 0℃预处理温度下获得了最好的器件性能 .10 0 0℃在 NMOS管中测得的电子迁移率达 314 cm2 / (V· s) ,分别比在 110 0℃和未做高温处理下的大 10 %和 2 2 % .10 0 0℃下器件的最大开关电流比也达到了 3× 10 8.对器件的进一步重复性研究证实了上述结果的可靠性     

热电Ca3Co4O9薄膜的一致取向生长及其激光感生电压效应

利用脉冲激光沉积(PLD)法,在蓝宝石(0001)平衬底上成功制备了c轴一致取向的Ca3Co4O9薄膜。利用X射线衍射(XRD)分析测定了薄膜的相结构和生长取向。研究了不同衬底温度与不同原位氧压对Ca3Co4O9薄膜结晶质量与生长取向的影响,确定了最佳生长条件。利用这一条件在倾斜Al2O3(0001)衬底上制备了Ca3Co4O9薄膜。研究发现,当Ca3Co4O9薄膜被波长248nm,脉冲宽度20ns的脉冲激光照射时,在薄膜两端存在较大的激光感生热电电压(LITV)信号,峰值电压达到4.4V,其上升沿为36ns,半峰全宽(FWHM)为131ns。可以认为这种激光感生热电电压信号是由于Ca3Co4O9薄膜面内与面间泽贝克(Seebeck)系数张量的各向异性引起的。     

Proton irradiation of CdTe thin film photovoltaics deposited on cerium‐doped space glass

Space photovoltaics is dominated by multi‐junction (III‐V) technology. However, emerging applications will require solar arrays with high specific power (kW/kg), flexibility in stowage and deployment, and a significantly lower cost than the current III‐V technology offers. This research demonstrates direct deposition of thin film CdTe onto the radiation‐hard cover glass that is normally laminated to any solar cell deployed in space. Four CdTe samples, with 9 defined contact device areas of 0.25 cm², were irradiated with protons of 0.5‐MeV energy and varying fluences. At the lowest fluence, 1 × 10¹² cm⁻², the relative efficiency of the solar cells was 95%. Increasing the proton fluence to 1 × 10¹³ cm⁻² and then 1 × 10¹⁴ cm⁻² decreased the solar cell efficiency to 82% and 4%, respectively. At the fluence of 1 × 10¹³ cm⁻², carrier concentration was reduced by an order of magnitude. Solar Cell Capacitance Simulator (SCAPS) modelling obtained a good fit from a reduction in shallow acceptor concentration with no change in the deep trap defect concentration. The more highly irradiated devices resulted in a buried junction characteristic of the external quantum efficiency, indicating further deterioration of the acceptor doping. This is explained by compensation from interstitial H⁺ formed by the proton absorption. An anneal of the 1 × 10¹⁴ cm⁻² fluence devices gave an efficiency increase from 4% to 73% of the pre‐irradiated levels, indicating that the compensation was reversible. CdTe with its rapid recovery through annealing demonstrates a radiation hardness to protons that is far superior to conventional multi‐junction III‐V solar cells.     

Flexible electronic skin with high performance pressure sensing based on PVDF/rGO/BaTiO3 composite thin film

The wearable intelligent electronic product similar to electronic skin has a great application prospect. However, flexible electronic with high performance pressure sensing functions are still facing great challenges. In this paper, the highly sensitive flexible electronic skin (FES) based on the PVDF/rGO/BaTiO₃ composite thin film was fabricated using the near-field electrohydrodynamic direct-writing (NFEDW) method. The PVDF/rGO/BaTiO₃ composite solution was directly written on flexible substrate by the NFEDW method to fabricate FES with micro/nano fiber structure, which has the function of sensing pressure with high sensitivity and fast response. The surface morphology and microstructure were characterized by SEM, AFM, and optical microscope in detail. The fabricated FES has high sensitivity (59 kPa⁻¹) and faster response time (130 ms). FES has been successfully applied to the detection of human motion and subtle physiological signals. The experimental results show that FES has good stability and reliability. FES can recognize human motion, and it has a broad application prospect in the field of wearable devices.     

电子器件冷却用微型热管的蒸发传热分析

通过对薄液膜蒸发传热以及热管壁轴向导热的分析，对三角形截面微型热管的蒸发段建立了蒸发传热模型。研究表明：薄液膜对热臂蒸发传热的作用远远大于厚液膜；固液接触角在蒸发段沿轴向逐渐变小；对存在加工圆角的热臂进行传热计算的时候，最小弯月面半径和加工圆角存在制约关系，不能简单的以加工圆角代替。     

Fabrication of organic thin film transistors on Polyethylene Terephthalate (PET) fabric substrates

In this paper organic thin film transistors (OTFTs) are directly fabricated on fabric substrates consisting of Polyethylene Terephthalate (PET) fibers. A key process is coating the polymer layers on the fabric in order to reduce the large surface roughness of the fabric substrate. Two polymers, i.e. polyurethane (PU) and photo-acryl (PA), are used to reduce the large surface roughness and simultaneously improve the process compatibility of the layers with the subsequent OTFTs processes while also retaining the original flexibility of the fabric. The surface roughness of the PU/PA-coated fabric is significantly reduced to 0.3 μm. Furthermore, the original flexibility of the PET fabric remained after coating of the PU/PA polymer layers. The mobility of the OTFTs fabricated on the PU-PA coated fabric substrate is 0.05 ± 0.02 cm²/V s when three PA layers and 90 nm thick pentacene layer were used. The performance does not vary even after 30,000 bending test.     

氮氧化硅薄膜红外吸收特性的研究

利用等离子体增强化学气相沉积法沉积氮氧化硅(SiOxNy)薄膜,通过X射线光电子能谱仪、傅里叶变换红外光谱仪、椭偏仪等表征技术,研究不同N2O与NH3流量比R条件下薄膜的组分、光学常数及红外吸收特性.研究结果表明:随着流量比R的增加,SiOxNy薄膜中O的相对百分含量提高,N含量降低,而Si含量基本不变;薄膜由于Si-...     

Ⅱ-Ⅵ族三元合金薄膜生长与掺杂工艺研究现状

相对于Ⅱ-Ⅵ族二元化合物,三元合金在调节带隙宽度和晶格常数上的灵活性使其应用前景更加广阔,并有希望解决Ⅱ-Ⅵ族材料普遍存在的单极性掺杂难题而成为未来新型光电器件发展的一个重要方向.文章着重介绍了分子束外延(MBE)技术生长ZnSeTe、CdZnTe、CdSeTe等Ⅱ-Ⅵ族三元合金单晶薄膜的研究现状,分析了MBE生长三元合金时需要考虑的问题,介绍了Ⅱ-Ⅵ族半导体材料n/p型掺杂的常用元素和掺杂方式,讨论了限制Ⅱ-Ⅵ族材料有效掺杂的物理机制和三元合金在掺杂方面的研究动态,并对三元合金薄膜的发展前景进行了展望.     

Interdigitated back‐contact heterojunction solar cell concept for liquid phase crystallized thin‐film silicon on glass

We present an interdigitated back‐contact silicon heterojunction system designed for liquid‐phase crystallized thin‐film (~10 µm) silicon on glass. The preparation of the interdigitated emitter (a‐Si:H(p)) and absorber (a‐Si:H(n)) contact layers relies on the etch selectivity of doped amorphous silicon layers in alkaline solutions. The etch rates of a‐Si:H(n) and a‐Si:H(p) in 0.6% NaOH were determined and interdigitated back‐contact silicon heterojunction solar cells with two different metallizations, namely Al and ITO/Ag electrodes, were evaluated regarding electrical and optical properties. An additional random pyramid texture on the back side provides short‐circuit current density (j_SC) of up to 30.3 mA/cm² using the ITO/Ag metallization. The maximum efficiency of 10.5% is mainly limited by a low of fill factor of 57%. However, the high j_SC, as well as V_OC values of 633 mV and pseudo‐fill factors of 77%, underline the high potential of this approach. Copyright © 2015 John Wiley & Sons, Ltd.     

Capillary instabilities in thin films

Very thin films, less than 100 nm-thick, are used in a variety of applications, including as catalysts and for thin film reactions to form patterned silicides in electronic devices. Because of their high surface to volume ratio, these very thin films are subject to cap-illary instability and can agglomerate well below their melting temperatures. In order to develop a general understanding of agglomeration in very thin films, we have studied initially continuous and patterned films of gold on fused silica substrates. Two in situ techniques were used to monitor agglomeration: 1) heating and video recording in a transmission electron microscope, and 2) measurement of the intensity of laser light transmitted through a sample heated in a furnace. Electron microscopy allowed inves-tigation of the role of the microstructure of the Au film and analysis of light transmis-sion during heating allowed determination of temperature-dependent and film-thick-ness-dependent agglomeration rates. These results will be described along with models for the agglomeration process.