Hydrogen related phenomena at the ITO/a‐Si:H/Si heterojunction solar cell interfaces
Hydrogen related phenomena at the ITO/a‐Si:H/Si heterojunction solar cell interfaces
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DOI：
10.1002/pssa.201200459
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
A. Ulyashin;A. Sytchkova
中科院分区：
文献类型：
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作者：
A. Ulyashin;A. Sytchkova
用原子力显微镜和扫描扩展电阻显微镜分析了a-Si：H和氧化铟锡(ITO)薄层的性质以及硅基异质结(HJ)ITO/(P)a-Si：H/n-Si结构的界面性质。结果表明，在n型抛光单晶硅或(P)a-Si：H/n-Si衬底上生长的ITO薄膜的形貌与沉积温度有关，并具有纳米尺度的特性。在ITO层的表面和本体上形成了高导电性的纳米点。观察到的纳米斑点和纳米点是由于在HJ太阳电池制备过程中在a-Si：H层上沉积ITO膜时氢引发还原过程的影响。对经过氢等离子体处理后的ITO表面的形貌特征的研究证实了这一事实。结果表明，氢引发的ITO表面导电纳米颗粒的形成不会从本质上改变ITO层的透明度。结果表明，ITO/a-Si：H界面上的导电纳米点可以看作是局部导电通道，它提供了流过ITO/(P)a-Si：H界面的电流，而不会对太阳电池结构造成本质上的遮蔽。这一发现为优化ITO/Si基HJ太阳电池的性能开辟了一条有趣的途径。
Properties of thin a‐Si:H and indium‐tin oxide (ITO) layers as well as properties of interfaces of Si based heterojunction (HJ) ITO/(p)a‐Si:H/n‐Si structures were analyzed by means of atomic force microscopy (AFM) and scanning spreading resistance microscopy. It is shown that the morphology of thin ITO layers grown on n‐type polished crystalline Si or on (p)a‐Si:H/n‐Si substrates depends on the deposition temperature and has peculiarities on nano‐scale. Formation of highly conductive nano‐dots on the surface and in the bulk of ITO layers is found. The observed nano‐spots and nano‐dots are attributed to the influence of hydrogen initiated reduction process, which occurs upon deposition of ITO films on an a‐Si:H layer during the fabrication process of a HJ solar cell. This fact is confirmed by investigation of morphological properties of ITO surfaces after treatment by hydrogen plasma. It is shown that formation of conductive nano‐particles on the ITO surface initiated by hydrogen does not change essentially transparency of an ITO layer. It is concluded that conductive nano‐dots at the ITO/a‐Si:H interface can be considered as local conductive channels, which provide a current flow through the ITO/(p)a‐Si:H interface without essential shadowing of the solar cell structure. This finding opens an interesting way for the optimization of properties of the ITO/Si‐based HJ solar cells.