Oxygen isoelectronic impurity in ZnSxTe1-x

The binding energy of excitons bound to oxygen isoelectronic impurity in ZnSxTe1-x, shows a remarkable scaling with the difference between the electronegativity of oxygen and the concentration-weighted average of those of S and Te. The signatures of the free exciton, observed with wavelength modulated reflectivity, and those of shallow acceptor bound excitons, revealed in photoluminescence, show an unmistakable redshift with increasing x (0 less than or equal to x less than or equal to 0.13). In striking contrast, the excitons bound to the isoelectronic oxygen center in these alloys manifest a blueshift with increasing x. [S0163-1829(99)51148-X].