氧与激光辐照对多孔硅光致发光光谱的影响

将化学腐蚀后的多孔硅样品分别置于大气和氧气中,用激光连续辐照其表面.观察到多孔硅的光致发光光谱峰位随辐照时间增加发生蓝移,最后达到稳定,在真空中作同样处理的多孔硅光致发光峰位却没有移动.X射线光电子谱测量结果表明,在大气及氧气中激光辐照的多孔硅层内并未探测到二氧化硅,结合红外吸收光谱实验,认为蓝移的原因可能是氧置换了多孔硅内表面的硅,出现Si-O-Si结构的结果.

EFFECT OF OXYGEN AND LASER ILLUMINATION ON PHOTOLUMINESCENCE OF POROUS SILICON

Porous silicon (PS) samples treated by chemical etching were illuminated with laser uninterruptedly in atmosphere and oxygen, respectively. The photoluminescence (PL) band of porous silicon exhibited a continuous blue shift with the time of illumination, at last it reached a stationary value. In vacuum, the sample was treated in the same way as mentioned above. But its PL band showed no shift. X-ray photoelectron spectroscopy showed that no SiO_2 was detected in the two PS layers which were illuminated in atmos- phere and oxygen, respectively. Combining it with the infrared absorption spectra measurement it is suggested that the blue shift of the PL band was attributed to the replacement of Si atom on the inner walls of PS by oxygen atom and the formation of the Si -O-Si structure.