Preparation and properties of bulk ZnSe: Cr single crytals

摘要

Cr-doped zinc selenide signle crystals have been prepared by a two stage process. In the firs stage, undoped signle crystals were grown by a sublimation travelign heater method (STHM) without seeding. The high quality of the as-grown crystals was confirmed by double crystal X-ray diffraction, which showed the full-width half-maximum (FWHM) of the rocking curves to be less than 20 arcsec on the (2 2 0) diffracion planes of the crystals. Selective chemicla etching showed dislocation density of these faces to be less than 5×10~4 cm~-2. IN the second stage, the ZnSe crystals were Cr-doped by the method of the thermal diffusion form a solid metal source. Cr concentration of 3.3×10~19 cm~-3, absorption coefficient of more than 30 cm~-1 at 1750 nm, and passive losses of less than 0.3 cm~-1 at 2500 nm were obtained under optimal technological conditions.