The S,Cu Centre in Silicon

It appears that no absorption measurements of (S,Cu) in the near IR has been reported, but absorption measurements of the isoelectronic donor centres associated with Sa and Sb have been performed at lower energies under continuous photoexcitation with a Nd-YAG laser operated at 1.06 or 1.32pm (1.17 or 0.939eV) by Beckett et al. [18]. At LHeT, the creation in the triplet state is predominant and the ground state for the EM spectra is therefore, the triplet states Sa° and Sb°. The photoinduced spectrum so obtained is displayed in Fig. 6.39. 

The positions of the lines and the energy levels related to this (S,Cu) centre are given in Table 6.36. 

The values of the hole binding energies of the (S,Cu) isoelectronic centre are 137 and 292meV for Sa and Sb, respectively. The ID ionization energies associated with this centre (65.28 and 66.21 meV) are significantly larger than those of the pseudo-donor (C,0) complexes associated with lines C and P, and this has been attributed to the (S,Cu) centre for a central-cell potential which is also attractive for electrons, but to a lesser extent than for holes [18]. 

The triplet line at 811.96meV (6548.9 cm-1) of the Sg centre has been measured by PL at 1.5 K in qmi 28Si natS and in qmi 28Si 34S samples [274]. As for absorption measurements in similar materials, the line becomes 

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