A PHOTOLUMINESCENCE STUDY OF ZN-O COMPLEXES IN SILICON

Samples of CZ silicon doped with zinc and annealed in the temperature range 500-700=degrees-C produce intense photoluminescence at liquid he lium temperatures. The majority of the luminescence occurs in two vibr onic bands with zero-phonon lines at 1129.57(5) meV and 1090.47(5) meV denoted Zn(A) and Zn(B) respectively. In both cases, split ground and excited states are observed. Isotope substitution experiments reveal that one zinc atom is incorporated in each of the defects. The spectra do not occur for FZ silicon unless oxygen is deliberately introduced in addition to zinc. We conclude that the defects are complexes of zin c and oxygen atoms which are produced during the annealing process but which dissociate for anneal temperatures above 700-degrees-C. Uniaxia l stress and magnetic field perturbation data show that the Zn(A) and Zn(B) defects are very similar in their structural and electronic prop erties. The spectra are attributed to electron-hole recombination at Z n-0 defects, but the details of the electron and hole configurations a nd the precise nature of the Zn-0 defects, but the details of the elec tron and hole configurations and the precise nature of the Zn-0 comple xes have not yet been determined.