@article{5886, author = {I. Tsimperidis and T. Gregorkiewicz and Hhpt Bekman and Cjgm Langerak}, title = {Direct observation of the two-stage excitation mechanism of Er in Si}, abstract = {In Er-doped silicon we have found direct evidence for the formation of the Er-related intermediate state that is a precursor of the final 4f-electron excited state responsible fur the 0.8 eV luminescence. Time-resolved photoluminescence following band-gap illumination shows disruption of this center by a THz pulse from a free-electron laser. The decay of the intermediate state could be directly monitored in this double-beam experiment and a lifetime of approximately 100 mu s has been found. Tn this way the most characteristic step in die excitation mechanism of the Er ion in silicon has been revealed experimentally. [S0031-9007(98)07761-8].}, year = {1998}, journal = {Physical Review Letters}, volume = {81}, number = {21}, pages = {4748-4751}, month = {Nov 23}, isbn = {0031-9007}, doi = {10.1103/PhysRevLett.81.4748}, language = {eng}, }