关键词: 
硅 /
薄膜 /
重离子辐照 /
光学带隙

摘要: 室温下， 用94 MeV的Xe离子辐照纳米晶和非晶硅薄膜以及单晶硅样品， 辐照量分别为1.0×10¹¹，1.0×10¹² 和1.0×10¹³ ions/cm²。 所有样品均在室温下用UV/VIS/NIR光谱仪进行检测分析。 通过对比研究了纳米晶、 非晶、 单晶硅样品的光学带隙随Xe离子辐照量的变化。 结果表明， 不同结构的硅材料中Xe离子辐照引起的光学带隙变化规律差异显著： 随着Xe离子辐照量的增加， 单晶硅的光学带隙基本不变， 非晶硅薄膜的光学带隙由初始的约1.78 eV逐渐减小到约1.54 eV， 而纳米晶硅薄膜的光学带隙则由初始的约1.50 eV快速增大至约1.81 eV， 然后再减小至约1.67 eV。 对硅材料结构影响辐照效应的机理进行了初步探讨。
Monocrystalline silicon(cSi), thin films of amorphous silicon(aSi) and nanocrystalline silicon(ncSi) were irradiated at room temperature(RT) by using 94 MeV Xeions at 1.0×10¹¹, 1.0×10¹² or 1.0×10¹³ Xeions/cm², respectively. All samples were analyzed at RT by an UV/VIS/NIR spectrometer (Lambda 900, PE, Germany), and then the uariation of the optical bandgap with the irradiation fluence was investigated systematically. The results show that the optical bandgap of the silicon samples irradiates by Xeion changed dramatically with different crystalline structures. For the aSi thin films, the optical bandgap values decreased gradually from ~1.78 to ~1.54 eV with increasing Xeion irradiation fluence. For the ncSi thin films, the optical bandgap values increased sharply from ~1.50 (origin) to ~1.81 eV(Φ=1.0×10¹²ions/cm²), and then decreased to ~1.67 eV(Φ=1.0×10¹³ ions/cm²). However, there is no observable change of the optical bandgap of the cSi after Xeion irradiations. Possible mechanism on the modification of the silicon thin films was briefly discussed.