CATHODOLUMINESCING PROPERTIES OF SPARK-PROCESSED SILICON

Spark-processed Si was characterized by temperature-dependent cathodoluminescence (CL) measurements. The CL spectra were recorded between 6 and 300 K. Two separated CL maxima were observed. The high-energy peak centred around 480 nm and the low-energy peak near 650 nm. Whereas the intensity of the red CL increased at lower temperatures, the intensity of the blue CL had a maximum near 230 K and then decreased continuously with decreasing temperatures. The integrated intensity for both CL bands remained essentially constant at temperatures below 270 K. This behaviour is interpreted in terms of a competitive radiative mechanism. Furthermore, the localized distribution of cathodoluminescing centres across the surface of a sample was studied by spectrally resolved CL micrographs. The results are discussed in comparison with the photoluminescing characteristics of spark-processed Si and in the light of the luminescing properties of porous Si.