Optimization of ZnSe growth on miscut GaAs substrates by molecular beam epitaxy

We report growth optimization of molecular beam epitaxy (MBE) grown ZnSe on GaAs (0 0 1) substrate tilted by 15° toward [1 1 0] in terms of beam equivalent pressure (BEP) ratio and growth temperature. A LT-ZnSe buffer was grown to reduce the formation of Ga–Se bonding, a well-known source of defect generation, due to interdiffusion through the heterointerface in the initial stage of growth. The ZnSe layer was further optimized by low-temperature-grown (LT-ZnSe) buffer. The optical and structural properties of the ZnSe film with LT-ZnSe and GaAs buffer are also analyzed by photoluminescence spectroscopy (PL), X-ray diffraction (XRD), and secondary ion mass spectroscopy (SIMS), which show very large intensity ratio of near-band-edge emission to deep level emission, narrow XRD peak width of (0 0 4) rocking curves, and abrupt ZnSe/GaAs heterointerface under the optimum growth condition, respectively. The optimum growth conditions are BEP ratio ( P Se / P Zn ) of 3 and growth temperature of 310°C with an LT-ZnSe buffer grown at 250°C.