INFLUENCE OF THE COMPOSITION ON THE INTERIMPURITY RADIATIVE RECOMBINATION IN GERMANIUM-SILICON ALLOYS.

An investigation was made of the interimpurity radiative recombination spectra of Ge//1// minus //xSi//x:Ga: As alloys with compositions in the range x less than equivalent to 0. 08. The following quantities were determined at 4. 2 degree K as a function of x: the positions of the zero-phonon and phonon (LA) luminescence bands; the ratio of the intensities of these bands; the half-width and decay kinetics of the zero-phonon luminescence band. The results indicated that Si formed clusters (with an average of 50 atoms in each) in germanium and that the alloys contained Si-As complexes responsible for the strong zero-phonon transition. In the x greater than 0. 04 range the nonequilibrium electrons were localized not at the As impurities but in potential wells due to fluctuations of the silicon concentration.