Auger valence electron spectra in Ca-silicides

CaSi2 and CaSi have been investigated by Auger Valence Electron Spectroscopy (AVES). Some drastic differences of the Auger peak due to 3s states in the Si atoms were observed in the Si[2s, 2p, V] Auger spectra. The peak that arised from valence electron states in the Ca atoms was observed in the Ca[2p,3p, V] Auger spectra for both Ca-silicides. This result suggests that the Ca-Si bonds are partially ionic. However, the number of the valence electrons in Ca atoms for CaSi was larger than that for CaSi2. This result implies that the part of homopolar bonds between the Si and Ca atoms in CaSi is stronger than that in CaSi2. Based on these results, it has been concluded that the change of the Si [2s, 2p, V] Auger spectra is associated with the difference of the part of homopolar bonds between the Si and Ca atoms.