激光在非晶硅薄膜太阳能电池制造中的应用

人类进入21世纪,能源问题更为突出,常规能源的匮乏不足,面临在有限资源和环保严格要求的双重制约下实现经济和社会可持续发展已成为全球热点问题。传统的石油、煤等化石能源的开发利用,在一定程度上带来了环境污染、温室效应     

非晶硅薄膜太阳能电池特性研究

介绍了太阳能电池的工作原理,并给出了太阳能电池的物理模型。设计了室内测试非晶硅薄膜电池输出特性的实验,并对实验结果进行分析。搭建了小型独立光伏发电系统,给出系统的工程设计结构。实验结果表明,太阳能电池的转换效率与室内实验所测得的结果相吻合,证明该系统具有可靠性和高效性。     

太阳能薄膜电池的研究现状及发展前景

介绍了太阳能薄膜电池的原理及其结构特点,并从材料成本、制作工艺方面分析了太阳能薄膜电池的发展前景及应用。介绍了目前几种主要的太阳能薄膜电池,分别对几种太阳能薄膜电池从原理、材料、光电转换效率等方面分析了其优缺点。总结出有机太阳能薄膜电池在薄膜电池中的优势以及发展前景,为太阳能薄膜电池的发展提供了一些建议。     

固体纳秒激光器应用于非晶硅薄膜结晶的研究

多晶硅薄膜比非晶硅薄膜具有更高的电子迁移率,在器件中表现出更优良的性能,脉冲激光结晶非晶硅薄膜制备多晶硅薄膜的方法具有热积存小、对衬底影响小、成本低等优点。使用532 nm固体纳秒激光器进行了非晶硅薄膜激光结晶实验,为了解决直接使用高斯光束结晶时因光斑能量分布带来的结晶效果不均匀,首先基于光束整型系统将圆形的高斯光束整型成为线性平顶光束,而后研究单脉冲能量密度、脉冲个数、非晶硅薄膜厚度对结晶效果的影响。结果表明,线性平顶光束用于非晶硅薄膜结晶具有更好的均匀性,对于100 nm非晶硅薄膜,随着能量密度的增加,晶粒逐渐变大,直到表面出现热损伤,最大晶粒尺寸约为1 μm×500 nm。随着脉冲个数的增加,表面粗糙度有减小的趋势,观察到的最小粗糙度约为2.38 nm。对于20 nm超薄非晶硅薄膜,只有当能量密度位于134 mJ/cm2和167 mJ/cm2之间、脉冲个数大于或等于八个时才能观察到明显的结晶效果。     

NIP型非晶硅薄膜太阳能电池的研究

采用射频等离子体增强化学气相沉积(RF-PECVD)技术制备非晶硅(a-Si)NIP太阳能电池,其中电池的窗口层采用P型晶化硅薄膜,电池结构为Al/glass/SnO2/N(a-Si:H)/I(a-Si:H)/P(cryst-Si:H)/ITO/Al.为了使P型晶化硅薄膜能够在a-Si表面成功生长,电池制备过程中采用了H等离子体处理a-Si表面的方法.通过调节电池P层和N层厚度和H等离子体处理a-Si表面的时间,优化了太阳能电池的制备工艺.结果表明,使用H等离子体处理a-Si表面5 min,可以在a-Si表面获得高电导率的P型晶化硅薄膜,并且这种结构可以应用到电池上;当P型晶化硅层沉积时间12.5 min,N层沉积12 min,此种结构电池特性最好,效率达6.40%.通过调整P型晶化硅薄膜的结构特征,将能进一步改善电池的性能.     

非晶硅薄膜的YAG激光晶化工艺研究

应用YAG激光器在不同工艺条件(激光脉冲频率及脉宽)下对非晶硅薄膜进行了微晶化处理。采用XRD和AFM对所制薄膜的物相结构和表面形貌进行了分析,并探索了激光脉冲占空比对非晶硅薄膜晶化的影响。结果表明,非晶硅薄膜在不同激光脉冲占空比情况下的结晶变化趋势均为多晶硅衬底表层先非晶化,后与非晶硅薄膜一起结晶,而利于其结晶的最佳占空比为1/25。已晶化硅薄膜的晶粒尺寸随占空比的增加先变大后变小。     

激光脉冲频率对不同衬底上非晶硅薄膜晶化的影响

应用不同频率的YAG激光分别对单晶硅及多晶硅衬底上的非晶硅薄膜进行了退火处理。晶化后的非晶硅薄膜的物相结构和表面形貌用XRD和AFM进行分析。XRD测试结果表明:随着激光频率的增加,两种衬底上的非晶硅薄膜晶化晶粒尺寸均出现了先增加后降低的现象。所有非晶硅样品的衍射峰位与衬底一致,说明非晶硅薄膜的晶粒生长是外延生长。从多晶硅衬底样品的XRD可以看出,随着激光频率的增加,激光首先融化衬底表面,然后衬底表层与非晶硅薄膜一起晶化。非晶硅薄膜最佳晶化激光频率分别为:多晶硅衬底20Hz,单晶硅衬底10Hz。     

可用于可穿戴设备的透明非晶硅薄膜太阳能电池的研究

一种可用于可穿戴设备屏幕表面的透明非晶硅薄膜太阳能电池,采用激光刻蚀高密度微纳光通道阵列、TCO薄膜作为透明导电背电极,并减薄I层厚度来提升光线透过率。实验表明随着光刻密度增加或I层厚度的减少,光电转换效率会降低,光线透过率会增加,当I层厚度300nm,光刻孔隙直径30m,阵列间隔55m以内时,可获得50%以上的透过率（最高59%）和2.5%以上的光电转化效率（最高3%）。     

Self-heating and kink effects in a-Si:H thin film transistors

We describe a new physics based, analytical DC model accounting for short channel effects for hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFT's). This model is based on the long channel device model. Two important short-channel phenomena, self-heating and kink effects, are analyzed in detail. For the self-heating effect, a thermal kinetic analysis is carried out and a physical model and an equivalent circuit are used to estimate the thermal resistance of the device. In deriving the analytical model for self-heating effect, a first order approximation and self-consistency are used to give an iteration-free model accurate for a temperature rise of up to 100°C. In the modeling of the kink effects, a semi-empirical approach is used based on the physics involved. The combined model accurately reproduces the DC characteristics of a-Si:H TFT's with a gate length of the 4 μm. Predictions for a-Si:H TFT's scaled down to 1 μm are also provided. The model is suitable for use in device and circuit simulators     

异质结硅太阳能电池a—Si：H薄膜的研究

通过应用Scharfetter-Gummel数值求解Poisson方程，对热平衡态P^ （a-Si:H)/n(c-Si)异质结太阳能电池进行计算机数值模拟分析。结果指出，采用更薄P^ (a-Si：H）薄膜设计能有效增强光生载流子的传输与收集，从而提高a-Si/c-Si异质结太阳能电池的性能。同时，还讨论了P^ (a-Si:h)薄膜中P型掺杂浓度对光生载流了传输与收集的影响。高强茺光照射下模拟，计算表明，a-Si/c-Si异质结结构太阳能电池具有较高光稳定性。     

High performance a-Si:H thin film transistors based on aluminum gate metallization

We present a systematic study of the sputter deposition conditions for aluminum thin films employed as gate metallization for high performance a-Si:H thin film transistors (TFTs). Here, we vary sputtering parameters such as deposition temperature, process pressure, and power, all of which have a strong bearing on the surface roughness of the film, including hillock generation induced by thermal processing. For example, at a low deposition temperature (30°C) and a low process pressure (5 mTorr), the surface roughness appeared to be significantly reduced. Transistors with gate metallization deposited under these conditions show a low leakage current (10 fA), an ON/OFF ratio better than 10⁸, and a mobility of 1.1 cm²/V s. In contrast, films deposited at 150°C and 10 mTorr, yield a degradation in mobility to 0.77 cm²/V s and an increase in leakage current to 1 pA, caused by the high interface roughness of the TFT channel due to hillock formation on the Al gate.     

聚酰亚胺衬底柔性非晶硅薄膜电池集成串联组件的研究

研究了柔性Si基薄膜太阳电池集成串联组件的制备与关键技术。对导电栅线在柔性薄膜太阳电池集成串联组件中的重要性进行了模拟计算,对柔性薄膜太阳电池激光刻蚀进行了理论分析与实验优化,并对柔性Si基薄膜太阳电池集成串联组件进行了设计与研制。在聚酰亚胺(PI)衬底上,通过卷对卷磁控溅射与卷对卷等离子增强化学气相沉积(PECVD)依次沉积复合背反射层Ag/ZnO、Si基薄膜层和透明导电膜层,采用激光刻蚀与丝网印刷工艺相结合实现集成串联,制备了柔性非晶Si(a-Si)薄膜太阳电池集成串联组件。柔性单结集成串联组件有效面积转换效率达到了4.572%(AM0),开路电压Voc=5.065V,填充因子FF=0.552。     

a-Si:H (alloy) p-i-n superlattice solar cell contacts

A means of increasing the open-circuit voltage of p-i-n amorphous silicon-based solar cells without degrading their other properties is proposed. This is accomplished through the use of superlattices that replace the n and p contact regions. The proposed structure is a-Si:H/a-Si_0.8N_0.2:H for the p contact and a-Si:H/a-Si_0.5C_0.5:H for the n contact. Using reasonable values for relevant parameters, the proposed structure may have an open-circuit voltage higher than that of present cells by as much as 0.20 V     

Efficiency of the a-Si:H solar cell and grain size of SnO2transparent conductive film

The relationship between average grain size on the surface of SnO2transparent conductive film and conversion efficiency of the a-Si:H solar cell was investigated. a-Si:H solar cells were fabricated on SnO2/glass substrates with various grain sizes. The cell structure was glass/p(SiC)-i-n/Al and the effective cell area was 4 × 10^-2cm². The reflectivity from the glass substrate was reduced to about 7 percent with increasing the grain size from 0.1 to 0.8µm, and the short-circuit current was inceased from 12 to 14mA/cm². A 7.9 percent of conversion efficiency was achieved using milky SnO2film of 0.4-µm average grain size at AM-100mW/cm².     

A study of the i/p interface for flexible n–i–p a-Si:H thin film solar cells

In this paper, the influence of i/p interface buffer layer on the performance of flexible n–i–p a-Si:H thin film solar cells is studied. The results show that the dopant distribution in the buffer layer has large effect on the property of solar cells. A larger open circuit voltage and fill factor can be obtained when methane is introduced into the chamber prior to diborane during the deposition of buffer layer. The AMPS simulation indicates that it is beneficial to improve the built-in electric field in the i layer when the carbon is doped prior to boron, thus the carrier transport properties are improved. By further optimizing the deposition parameter, an initial conversion efficiency of 5.668% is achieved for the a-Si:H thin film solar cells on the PI substrates at 150 °C.     

薄膜太阳能电池的研究进展

薄膜太阳能电池是缓解能源危机的新型光伏器件。评述了薄膜太阳能电池的优缺点,主要介绍了薄膜硅太阳能电池、多元化合物薄膜太阳能电池和有机薄膜太阳能电池的研究现状,总结了它们各自在价格成本、光电转换效率及对环境影响等方面的特点,并对其发展趋势进行了展望。