Development of nc-Si/ a -SiN x :H Thin Films for Photovoltaic and Light-Emitting Applications
Development of nc-Si/ a -SiN x :H Thin Films for Photovoltaic and Light-Emitting Applications
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DOI：
10.1166/sam.2013.1446
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发表时间：
2013-02
影响因子：
0.9
通讯作者：
B. Sain;D. Das
中科院分区：
文献类型：
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作者：
B. Sain;D. Das
采用RFICPCVD法，在13.56 MHz频率下，通过改变300 °C稀氢等离子体中的流量比R = NH3/SiH 4，制备了镶嵌在非晶氮化硅基质中的纳米硅（nc-Si/a-SiNx：H）。硅网络中的氮结合以各种方式控制纳米结晶的性质：然而，通过降低总结晶度，增强超纳米晶组分，有效地将平均晶粒尺寸从14 nm降低到2.2 nm，从而增加光学带隙，并同时增加由220 μ m的相对优势所表现出的结晶上优选的晶粒的量晶体取向nc-Si/a-SiN x：H薄膜具有较强的蓝光发射，在413 nm和438 nm处有两个发射峰，在467 nm和498 nm处有两个发射肩，其相对变化分别与Si超纳米晶浓度的增加和网络沿着氮化增强的辐射Si悬挂键以及随后在相对非晶结构下氧污染的影响减弱有关。减小硅纳米晶体的尺寸，同时控制其在宽禁带nc-Si/a-SiN x：H内的晶体学上优选的220 nm晶体取向的生长，其表现出强蓝光发射，值得在第三代全硅串联结构太阳能电池和发光器件的制造中有效利用的巨大前景。
Silicon nanocrystals embedded in amorphous silicon-nitride matrix (nc-Si/a-SiN x :H) were prepared using RFICPCVD at 13.56 MHz, by changing the flow ratio R = NH3/SiH4 in the H2-diluted plasma at 300 °C. Nitrogen incorporation in silicon network controls the nature of nanocrystallinity in various ways: by reducing overall crystallinity, however, enhancing the ultra-nanocrystalline component, efficiently reducing the average grain size from 14 to 2.2 nm, thereby increasing the optical band gap, and simultaneously increasing the amount of thermodynamically preferred crystalline grains exhibited by the relative dominance of 〈220〉 crystallographic orientation. The nc-Si/a-SiN x :H films exhibit strong blue light emission that consists of two peaks at 413 and 438 nm and two shoulders around 467 and 498 nm, the relative changes of which are associated, respectively, to the rising concentration of Si ultra-nanocrystals and enhanced radiative Si dangling bonds at growing nitrogenation of the network along with subsequent weakening of the effect of oxygen contaminant at relatively amorphous structure. Size reduction of silicon nanocrystals with simultaneous control of its growth at thermodynamically preferred 〈220〉 crystallographic orientation within wide band gap nc-Si/a-SiN x :H that exhibit strong blue light emission, deserves enormous promise towards efficient utilization in the fabrication of third-generation all-silicon tandem structure solar cells and light emitting devices.