IMPURITY INCLUSIONS IN EXTRA-PURE ARSENIC AND CHALCOGENS

Commercially available sulfur, selenium, tellurium, and arsenic are sh own to contain impurity inclusions 0.07 to 0.3 mu m in size, consistin g mainly of carbon. Without additional purification, the concentration of these inclusions in extrapure samples ranges from 10(6) to 10(9) c m(-3). Special purification procedures, taking into account the partic ular behavior of submicron particles, make it possible to reduce the c oncentration of inclusions to at least 10(4)-10(5) cm(-3). The presenc e of carbon particles in chalcogens and arsenic should be taken into a ccount when using these materials for synthesis of optical and semicon ductor materials.