利用Raman散射光谱研究铜铟镓硒薄膜表面的掺杂调节作用

主要研究了采用溅射后硒化方法制备CIGS(铜铟镓硒)薄膜太阳电池的吸收体材料中的表面层掺杂调节问题。并利用Raman散射谱分析研究了样品表面层特征峰的移用,研究结果表明: CIGS薄膜表面层由富In表面层调节为富CuGa表面层后,Raman特征峰位向高波数移动,表明薄膜表面的Ga含量随之变化,并导致表面能带的相应改变,经计算证实了富CuGa表面层样品较之富In表面层样品具有更高的表面能带,从而改善了以此材料为吸收层的太阳电池器件性能, V_oc提高了74 mV,填充因子上升8％,最终使器件转换效率η相应提高了约2％。提高了V_oc与FF。同时表明Raman散射谱作为一种灵敏的表面表征手段,在研究太阳电池吸收层表面状态时十分有力。     

供应中断风险下制造商的后备采购与改善努力策略比较研究

在供应中断风险环境下,对制造商的后备采购策略和改善努力策略进行了比较分析.研究发现,制造商在改善努力策略时向主供应商的采购数量恒大于在后备采购策略时的采购数量.改善努力与后备采购策略的收益差总是随着改善努力成本投入的增大而呈现出递减的规律.当努力成本投入变得不经济时,制造商将放弃对主供应商的改善努力.     

Cu（In,Ga）Se2 Thin Films on Flexible Polyimide Sheet： Structural and Electrical Properties versus Composition

The structural and electrical properties of Cu（In,Ga）Se2 （CIGS） films grown on polyimide （PI） sheet using the three-stage co-evaporation process are investigated by x-ray diffraction spectra （XRD）, scanning electron microscopy （SEM）, Raman spectra, and Hall effect measurements, respectively. The results show that the properties of CIGS films on PI sheet are strongly dependent on the compositional ratio of Cu/（In＋Oa） （Cu/Ⅲ）. In contrast to the non-stoichiometric CIGS films, stoichiometric CIGS films show better structural and electrical properties, such as a relatively larger grain size, lower resistivity and higher carrier concentration. The flexible CIGS solar cells on PI sheet with the conversion efficiencies of 9.7% and 6.6% are demonstrated for the CIGS absorber layer with Cu/Ⅲ of 0.96 and 0.76, respectively （active area, 0.20cm^2）. The cell efficiency for Cu-poor CIGS films is limited by a relatively lower open circuit voltage and fill factor.     

Cu(In,Ga)Se_2薄膜表面镓(Ga)含量分布对太阳电池性能的影响

本文利用三步法共蒸发制备Cu(In,Ga)Se_2多晶薄膜吸收层,通过改变第三步Ga的蒸发温度控制薄膜表面Ga的含量及其分布.随着吸收层表面Ga含量的增大,空间电荷区带隙变宽,电池的开路电压V_(oc)明显增大.同时,Ga的梯度分布有效地扩宽了吸收层的光谱响应范围,减小了由于禁带宽度增大所引起的短路电流J_(sc)的损失,从而有效地提高了电池的转换效率.     

RF-PECVD制备微晶硅薄膜的X射线衍射研究

采用X射线衍射(XRD)技术连续扫描法和薄膜衍射法对RF-PECVD制备的微晶硅薄膜结构进行了研究.改变硅烷浓度和反应功率,控制薄膜的生长速率,已达到制备不同材料的目的.根据硅基薄膜的电学特性和XRD测试,随着反应功率的增加,硅基薄膜的生长速率不断提高,微晶硅薄膜的晶化程度不断增大.     

中频对向靶磁控溅射制备超薄ZnO薄膜及其在太阳电池中的应用

中频溅射制备ZnO薄膜可改善射频磁控溅射方式中沉积速率过慢的缺点.对于多层薄膜的制备,对向靶的设计可使样品避开等离子体直接轰击,减少基底薄膜的损伤.本文采用这项技术制备厚度约为50nm的ZnO薄膜,通过调整工作压强、溅射功率、氧氩比等工艺条件,制备出均匀致密,结晶质量高,电阻率在102～103Ω·cm之间,可见光区透过率达到90;的ZnO薄膜.将其应用到CIGS太阳电池中发现,具有50nm厚度的ZnO层的CIGS太阳电池的性能较无ZnO层的太阳电池都有了很大提高.     

Fluid mud transportation at water wedge in the Changjiang Estuary

In situ data show that fluid mud of the Changjiang Estuary consists of fine sediment ranging from 8 to 11.5μm (median grain-size) including 28.8%-36.4% of clay. The composition of the clay is illite, chlorite, kaolinite and montmoillonite. The FM is a layer of high sediment concentration near the bed and results from flocculation under the environment of salt and fresh water mixing. Three kinds of FM have been identified under typical dynamic conditions: the first one is formed at slack water of ebb tide during the flood season, with the characteristics of extended area and low thickness; the second one is formed following a storm, characterized by large area and larger thickness; the third one is formed around the front of the saltwater wedge, characterized by small area but large thickness. In the dredged channel, the FM can be accumulated up to 1 m thick. In general, FM will change with the alternation from spring to neap tides, flood and dry seasons. Drastic change can happen during storms. At the s     

基于Nd:YAG/Cr:YAG/YAG键合晶体LD侧面泵浦激光器

利用Nd∶YAG/Cr∶YAG/YAG键合晶体,建立了具有高平均输出功率的LD侧面泵浦被动调Q激光器系统.当Cr∶YAG的初始透过率为85%、最大泵浦光功率为187.5 W时,1 064nm激光的平均输出功率为83.68W.通过KTP晶体进行倍频,在最大泵浦光功率下,产生了27.2W532nm绿光激光脉冲,同时脉冲宽度和重复频率分别为210ns和21.2kHz;绿光单脉冲能量和峰值功率分别为1.28mJ和6.1kW;泵浦光(808nm)到倍频光(532nm)的光-光效率为14.5%.     

Developments of High-Efficiency Flexible Cu（In,Ga）Se2 Thin Film Solar Cells on a Polyimide Sheet by Sodium Incorporation

We present the fabrication of flexible Cu（In,Ga）Se2 （CIGS） solar cells on a polyimide （PI） sheet with and without Na incorporation. A sodium element is incorporated into the CIGS absorber by using a NaF precursor after Mo back contact deposition. X-ray diffraction patterns show that the （112） preferred orientation of the as-grown GIGS films is decreased by Na incorporation. The secondary phase of （Inx,Gal-x）zSe3 is observed for the CIGS films with Na. There is no significant difference in the grain size with and without Na incorporation from surface and cross-sectional SEM images. Additionally, the increase of carrier concentration and decrease of resistivity of CIGS absorber are induced by Na doping. Finally, the flexible CIGS solar cells on PI sheets with efficiency close to 11%, containing Na, are achieved. The improvement of cell efficiency can be attributed to the modified electrical properties of the CIGS film by Na incorporation.