快重离子辐照对非晶态SiO_2薄膜光致发光谱的影响

Effects of Swift Heavy Ion Irradiations on the Photoluminescent Properties of Amorphous SiO_2 Thin Films

用湿氧化法在单晶硅表面生长了非晶态SiO2薄膜,再用高能Pb和Xe离子对薄膜进行辐照,最后用荧光光谱分析了辐照参数(剂量、电子能损值)与发光特性改变的相关性。研究发现,快重离子辐照能显著影响薄膜的发光特性,进一步分析显示,辐照导致了SiO2薄膜内O—Si—O缺陷、缺氧缺陷和非桥式氧空位缺陷的产生,且缺氧缺陷和非桥式氧空位缺陷的数量会随Pb离子辐照剂量的增加而增多,而O—Si—O缺陷和缺氧缺陷的形成需要较高的电子能损值。

Amorphous SiO2 thin films with about 500 nm in thickness were thermally grown on single crystalline silicon.These SiO2/Si samples were irradiated at room temperature（RT） by 853 MeV Pb-ions to 5×1011,1×1012,2×1012 or 5×1012 ions/cm2,and by 308 MeV Xe-ions to 1×1012 or 5×1012 ions/cm2,respectively.The variation of photoluminescence（PL） properties of these samples was investigated at RT using a fluorescent spectroscopy.The obtained results showed that Pb/Xe-ion irradiation led to significant changes of the PL properties and the variation of the PL properties depend strongly on the fluence of the Pb-ion irradiations and electronic energy loss of ions.For examples,huge PL peaks located at about 473 nm and 645 nm can be seen in PL spectra of 5×1012 Pb-ions/cm2 irradiated sample.Furthermore,with increasing of Pb-ion irradiation dose the intensity of these PL peaks increased.This implied that some micro-structure modifications like defects were induced by swift heavy ion irradiations,such as non-bridging oxygen defects（≡SiO·）,oxygen-vacancies defects（≡Si—Si） and Si—O related defects（O—Si—O）.Special light emitters will be achieved by using proper ion irradiation conditions,and it will be very useful for the synthesis of new type of SiO2-based light-emission materials.