Lithium-gold-related complexes in p-type crystalline silicon

Using Hall and conductivity measurements the formation of a Li-Au-related complex in p-type crystalline silicon is demonstrated. Substitutional gold is known to introduce two energy levels in the band gap of silicon, a deep acceptor level at E_c-0.56 eV and a deep donor level at E_v+0.34 eV. We observe two energy levels introduced by lithium diffusion of Au-doped silicon, a previously reported acceptor at E_c-0.41 eV in n-type Si:Au and a new level at E_v+0.41 eV in p-type Si:Au. In addition, control of the Li-doping level of p-type Si is found to shift the Fermi level position between the deep donor level to the deep acceptor level as expected, thus confirming their presence in the samples. We discuss the identity of these levels in comparison with theoretical predictions for the interaction between hydrogen and the energy levels of substitutional Au in silicon.