Characteristics of ZnCdTe grown on (100) GaAs substrate by MOCVD

To predict the Zn composition accurately in the ZnCdTe compound alloys, the estimation of solid-vapor distribution functions (SVDFs) from equilibrium thermodynamics on ternary II-VI compound semiconductors is applied to the growth of ZnCdTe alloys. Epitaxial layers of ZnCdTe grown on (100) GaAs substrates were performed by metalorganic chemical vapor deposition using DMCd, DETe, and DEZn as the material sources. Surface morphologies, film orientations, optical properties and quality of ZnCdTe epilayers related to the growth conditions were characterized by optical microscopy, X-ray diffraction, photoluminescence, and X-ray double-crystal rocking curve (DCRC) measurements. The best film quality was reported at a growth temperature of 350°C with a VI/II ratio of 0.57. The corresponding full width at half-maximum (FWHM) and x values of Zn_xCd_1-xTe films measured by DCRC and scanning electron microscope energy dispersive X-ray analysis were 180 arcsec and 0.07, respectively. The measured Zn composition in ZnCdTe can be estimated from the calculated results with good agreement.