不同激发波长下多孔硅的光致发光研究

采用阳极氧化法腐蚀n型Si(111)片,制备了多孔硅样品.利用荧光分光光度计对样品光致发光和光致发光激发特性进行了研究,发现多孔硅样品的光致发光谱上有2个发光峰,其中心分别位于640 nm和565 nm.基于前人的报道和本实验结果的分析,认为多孔硅的光致发光来源于纳米硅颗粒中光生载流子弛豫到其表面态上然后发生辐射复合.进一步通过实验证明,640 nm处的发光峰与纳米硅颗粒表面的Si-O复合物有关,而565 nm处的发光峰与其它发光中心有关.

Study on photoluminescence of porous silicon with different excitation wavelength

Porous silicon sample is prepared by anodization of n-type(111) silicon wafer.The photoluminescence properties are studied with fluorescence spectrophotometer.The photoluminescence spectra show two emission peaks locate at 640 nm and 565 nm.Based on the previous reports and the results shown here,we propose that PL result from the fact that after generated in the nanocrystalline silicon by photon pumping,the carriers relax into the surface states and then make a radiative recombination.It is proved that the peak at 640 nm is correlated with Si-O complexs and the peak at 565 nm is correlated with other luminescence center.