硅纳米晶体在太阳电池中的应用

硅纳米晶体的电子和光学特性使其在改善太阳电池的性能方面扮演着重要角色。目前,硅纳米晶体在太阳电池中应用的主要方式有利用纯硅纳米晶体薄膜制作太阳电池、硅纳米晶体与无机(氧化硅、氮化硅或碳化硅等)或有机(P3HT)薄膜基质结合构成复合结构太阳电池、硅纳米晶体与碳纳米结构(富勒烯或单壁碳纳米管)结合形成复合结构、硅纳米晶体与传统的染料敏化太阳电池结合、利用硅纳米晶体的减反射或下转换作用将硅纳米晶体与体硅太阳电池结合。硅纳米晶体也有可能在新概念太阳电池如多激子太阳电池、中间带太阳电池和热载流子太阳电池中得到应用。     

硅薄膜中的结构缺陷研究进展

硅薄膜作为制备硅薄膜太阳电池的重要材料,得到了广泛研究和应用,而硅薄膜中的各种缺陷及缺陷密度则对薄膜电池的转换效率和稳定性有着至关重要的影响。对硅薄膜中的缺陷种类、缺陷研究方法以及缺陷对薄膜性能的影响进行总结,期望对提高和改善硅薄膜质量乃至硅薄膜太阳电池转换效率和稳定性提供一定的指导。     

纳米硅薄膜及磁控溅射法沉积

纳米硅薄膜具有卓越的光学和电学特性,其在光电器件方面潜在的应用越来越引起人们的兴趣.讨论了用磁控溅射法制备纳米硅薄膜的微观机理及沉积参数对薄膜结构和性能的影响.其中,氢气分压、基片温度、溅射功率是磁控溅射法沉积纳米硅的关键参数,适当的温度、较高的氢气分压和较低的溅射功率有利于纳米硅的生成.     

掺磷纳米硅薄膜的制备及介观力学性质与介观接触电阻的研究

采用PECVD法制备的纳米硅薄膜是一种具有特殊性能的人工材料.它是由大量具有纳米量级的硅微品粒构成,纳米硅晶粒镶嵌在由非晶硅构成网络中,其晶粒所占的体积百分比为Xc≈50%,从而决定了其特有的性质.本文通过严格控制薄膜生长的工艺参数,得到了掺磷纳米硅薄膜,并通过原位纳米力学电学测试系统对其力学和电学性质进行测试,发现掺磷纳米硅薄膜的纳米硬度为5 GPa,而其杨氏模量随着压入深度的增加而增大,其接触电阻与薄膜的结构密切相关.这些属性对于纳米硅薄膜微器件的制备具有重要的参考意义.     

PCVD法制备硅系纳米复合薄膜材料

纳米复合薄膜材料由于具有传统复合材料和现代纳米材料两者的优点,成为重要的前沿研究领域之一.其中半导体纳米复合材料,尤其是硅系纳米复合薄膜,由于具有独特的光电性能,加之与集成电路相兼容的制备技术,有着广泛的应用前景.近年来关于纳米复合薄膜的研究不断深入,但仍有许多问题没有完全解决.本文围绕硅系纳米复合薄膜的材料特点,说明了等离子体化学气相沉积(PCVD)技术的工作原理和装置结构,以及该技术在硅系纳米复合薄膜制备中的独特优点.并以氮化硅薄膜为重点,介绍纳米复合薄膜材料的PCVD制备技术.文章最后对硅系纳米复合薄膜的在光电技术等各个领域的应用前景做了一些展望.     

铜锌锡硫薄膜太阳电池及其研究进展

近些年,人们越来越关注太阳辐射的光伏利用。光伏发电技术在迅猛发展,薄膜太阳电池从占有主导地位的硅晶片技术中抢占了一定的市场份额。其中铜锌锡硫薄膜太阳电池因具有低成本、高的光电转化效率和吸收系数、合适的禁带宽度和环境友好等优点成为近年来薄膜太阳电池研究的热点。本文阐述了铜锌锡硫薄膜太阳电池的器件结构和性能特点,介绍了铜锌锡硫薄膜太阳电池的制备方法和研究进展,并对今后主要的发展方向进行了展望。     

太阳电池用低温激光加工织构硅

英国色雷大学先进工艺研究所（ATI）开发出一种薄膜硅处理工艺,用低温紫外激光脉冲照射可将非晶硅转化成纳米晶硅。通过对脉冲对硅膜织构的深入探索发现,借此可以制造有机．无机混合太阳电池,电池具有已知纳米硅的最高效率,同时还类似于聚合物（MEH-PPV）。     

玻璃基片硅薄膜太阳电池的制备与研究现状

硅薄膜太阳电池已成为太阳电池研究的一个热点.主要阐述了玻璃基片硅薄膜太阳电池的制备方法以及研究进展,提出了影响发展的几种因素以及在以后的研究中需重点解决的问题.     

硅基薄膜太阳电池窗口材料的研究进展

综述了硅基薄膜太阳电池窗口材料的发展及应用现状,比较分析了几种常用窗口材料的光电性能,并讨论了掺杂剂的影响.最后展望了太阳电池窗口材料的研究和发展趋势.     

纳米硅薄膜研究进展

纳米硅薄膜具有独特的结构和许多优异的光电性能,可望应用于新型光电器件、大规模集成电路等领域。本文从制备技术、沉积机理、结构和性能各方面对纳米硅薄膜的研究进展情况作了回顾和综述,并对其发展前景作了展望     

Surface passivation of crystalline silicon by Cat-CVD amorphous and nanocrystalline thin silicon films

In this work, we study the electronic surface passivation of crystalline silicon with intrinsic thin silicon films deposited by Catalytic CVD. The contactless method used to determine the effective surface recombination velocity was the quasi-steady-state photoconductance technique. Hydrogenated amorphous and nanocrystalline silicon films were evaluated as passivating layers on n- and p-type float zone silicon wafers. The best results were obtained with amorphous silicon films, which allowed effective surface recombination velocities as low as 60 and 130 cm s⁻¹ on p- and n-type silicon, respectively. To our knowledge, these are the best results ever reported with intrinsic amorphous silicon films deposited by Catalytic CVD. The passivating properties of nanocrystalline silicon films strongly depended on the deposition conditions, especially on the filament temperature. Samples grown at lower filament temperatures (1600 °C) allowed effective surface recombination velocities of 450 and 600 cm s⁻¹ on n- and p-type silicon.     

Novel aspects in thin film silicon solar cells-amorphous, microcrystalline and nanocrystalline silicon

The improvement of photodegradation of a-Si:H has been studied on the basis of controlling the subsurface reaction and gaseous phase reaction. We found that higher deposition temperature, hydrogen dilution and triode method are effective to reduce the SiH₂ density in the film and to suppress the photodegradation of solar cells. These results are explained in terms of the hydrogen elimination reaction in the subsurface region and the contribution of the higher silane radicals to the film growth. The high-rate deposition of μc-Si:H was obtained by means of a high-pressure method and further improvement in deposition rate and the film quality was achieved in combination with the locally high-density plasma, which enables effective dissociation of source gases without thermal damage. It was also found that the deposition pressure is crucial to improve the film quality for device. This technique was successfully applied to the solar cells and an efficiency of 7.9% was obtained at a deposition rate of 3.1 nm/s. The potential application of nanocrystalline silicon is also discussed.     

Capacitance analyses of hydrogenated nanocrystalline silicon based thin film transistor

The capacitance-voltage (C-V) measurements within 10⁶-10^− 2 Hz frequency range were performed on the hydrogenated nanocrystalline silicon (nc-Si:H) bottom-gate thin film transistor (TFT) and metal-insulator-amorphous silicon (MIAS) structure, mechanically isolated from the same TFT. It was found that the conducting thin layer in nc-Si:H film expands the effective capacitor area beyond the electrode in the TFT structure, which complicates its C-V curves. Considering the TFT capacitance-frequency (C-F) curves, the equivalent circuit of the TFT structure was proposed and mechanism for this area expansion was discussed. On the other hand, the MIAS C-F curves were fitted by the equivalent circuit models to deduce its electrical properties. nc-Si:H neutral bulk effect was revealed by the dependence of the MIAS capacitance on frequency within 10⁶-10³ Hz at both accumulation and depletion regimes. The inversion in MIAS was detected at 10²-10^− 2 Hz for relatively low negative gate bias without any external activation source. The presence of the ac hopping conductivity in the nc-Si:H film was inferred from the fitting. In addition, the density of the interface traps and its energy distribution were determined.     

Preparation of ITO thin films applied in nanocrystalline silicon solar cells

ITO thin films were prepared by changing the experimental parameters including gas flow ratio, sputtering pressure and sputtering time in DC magnetron sputtering equipment. The stable experimental parameters of Ar flow at 70 sccm, O₂ flow at 2.5 sccm ∼ 3.0 sccm, sputtering pressure around 0.5 Pa, and sputtering time of 80 s were obtained. Under these parameters, we had achieved the ITO thin films with low resistivity (<4 × 10⁻⁴ Ω ? cm) and high average transmissivity (95.48%, 350 nm ∼ 1100 nm). These ITO thin films were applied in nanocrystalline silicon solar cells as top transparent conductive layer. The solar cell test result showed that the open circuit voltage (Voc) was up to 534.9 mV and the short circuit current density (Jsc) was 21.56 mA/cm².     

氢稀释对纳米晶硅薄膜微结构的影响

采用电感耦合等离子体化学气相沉积技术制备了氮化纳米硅薄膜,利用Raman散射、x射线衍射、红外吸收等技术对不同氮稀释条件下薄膜的微观结构和键合特性变化进行了研究.结果表明,较高的氢稀释比导致薄膜从非晶硅到纳米晶硅的结构转化,随着氮稀释比的增加,所沉积薄膜的晶化度及纳米晶硅的晶粒尺寸单调增加,纳米硅颗粒呈现在(110)方...     

Preparation of ITO thin films applied in nanocrystalline silicon solar cells

ITO thin films were prepared by changing the experimental parameters including gas flow ratio, sputtering pressure and sputtering time in DC magnetron sputtering equipment. The stable experimental parameters of Ar flow at 70 sccm, O₂ flow at 2.5 sccm ∼ 3.0 sccm, sputtering pressure around 0.5 Pa, and sputtering time of 80 s were obtained. Under these parameters, we had achieved the ITO thin films with low resistivity (<4 × 10⁻⁴ Ω ∙ cm) and high average transmissivity (95.48%, 350 nm ∼ 1100 nm). These ITO thin films were applied in nanocrystalline silicon solar cells as top transparent conductive layer. The solar cell test result showed that the open circuit voltage (Voc) was up to 534.9 mV and the short circuit current density (Jsc) was 21.56 mA/cm².     

掺硼nc-Si:H薄膜中纳米硅晶粒的择优生长

利用等离子体增强化学气相沉积(PECVD)生长的系列掺硼氢化纳米硅(nc-Si:H)薄膜中纳米硅晶粒(nanocrystallinesilicon,简称nc-Si)有择优生长的趋势。用HRTEM、XRD、Raman等方法研究掺硼nc-Si:H薄膜的微观结构时发现:掺硼nc-Si:H薄膜的XRD只有一个峰,峰位在2θ≈47o,晶面指数为(220),属于金刚石结构。用自由能密度与序参量的关系结合实验参数分析掺硼nc-Si:H薄膜择优生长的原因是:适当的电场作用引起序参量改变,导致薄膜在适当的自由能范围内nc-Si的晶面择优生长。随着掺硼浓度的增加,nc-Si:H薄膜的晶态率降低并逐步非晶化。nc-Si随硅烷的稀释比增加而长大,但晶态率降低。nc-Si随衬底温度升高而长大,晶态率提高。nc-Si随射频功率密度的增大而长大,晶态率增大的趋势平缓。但未发现掺硼浓度、稀释比、衬底温度、射频功率密度的变化引起薄膜中nc-Si晶面的择优生长。     

Anisotropic crystallite size analysis of textured nanocrystalline silicon thin films probed by X-ray diffraction

A newly developed X-ray technique is used, which is able to quantitatively combine texture, structure, anisotropic crystallite shape and film thickness analyses of nanocrystalline silicon films. The films are grown by reactive magnetron sputtering in a plasma mixture of H₂ and Ar onto amorphous SiO₂ and single-crystal (100)-Si substrates. Whatever the used substrate, preferred orientations are observed with texture strengths around 2-3 times a random distribution, with a tendency to achieve lower strengths for films grown on SiO₂ substrates. As a global trend, anisotropic shapes and textures are correlated with longest crystallite sizes along the 〈111〉 direction but absence of 〈111〉 oriented crystallites. Cell parameters are systematically observed larger than the value for bulk silicon, by approximately 0.005-0.015 Å.     

Correlating Raman-spectroscopy and high-resolution transmission-electron-microscopy studies of amorphous/nanocrystalline multilayered silicon thin films

The nanostructure of multilayered silicon thin films was studied using Raman spectroscopy (RS) and high-resolution transmission electron microscopy (HRTEM). Since the properties of nanocrystalline silicon layer depend on the size of the nanocrystals, an accurate determination of the crystallite sizes and the crystalline fraction is of primary importance. The average sizes of the nanocrystals estimated by RS, assuming bi-modal distribution of crystal sizes, were close to 2 nm and above 5-20 nm. HRTEM confirmed the existence of nanocrystals with a mean square value of around 2 nm and certain number of larger nanocrystals, embedded in an amorphous matrix. The correlation between the results obtained by these two techniques is discussed. The optical properties of measured samples corresponded to an amorphous-crystalline mixture with indication of confinement effects compatible with 2 nm nanocrystals.