Growth and annealing of zinc-blende CdSe thin films on GaAs (001) by molecular beam epitaxy

Abstract: CdSe thin films have been grown on GaAs (001) substrates by molecular beam epitaxy (MBE). The effects of substrate temperature and annealing treatment on the structural properties of CdSe layers were investigated. The growth rate slightly decreases due to the accelerated desorption of Cd from CdSe surface with an increase in the temperature. The sample grown at 260°C shows a polycrystalline structure with rough surface. As the temperature increases over 300°C, crystalline CdSe (001) epilayers with zinc-blende structure are achieved and the structural quality is improved remarkably. The epilayer grown at 340°C displays the narrowest full-width at half-maximum (FWHM) from (004) reflection in double-crystal X-ray rocking curve (DCXRC) and the smallest root-mean-square (RMS) roughness of 0.816nm. Additionally, samples fabricated at 320°C were annealed in air for 30min to study the films’ thermal stability. X-ray diffraction (XRD) results indicate that the zinc-blende structure remains unchanged when the annealing temperature is elevated to 460°C, meaning a good thermal stability of the cubic CdSe epilayers. [Copyright &y& Elsevier]