Fabrication of Short Period ZnSe-GaAs Superlattices by MOVPE

ABSTRACTThe growth condition and the structural properties of short period ZnSe-GaAs superlattices grown by metalorganic vapor phase epitaxy (MOVPE) are described. First, the growth condition was investigated. Superlattices (SLs) grown at 450°C have better structural property than those grown at 500°C. The thickness fluctuation of each constituent layer was investigated by means of the X-ray diffraction analysis, and it was indicated that the fluctuation in the fabricated structure was within 1 and 2 monomolecular layers for GaAs and ZnSe, respectively. Further optimization for growing thinner layers successfully brought SL with 25Å well and 140Å barrier layers. X-ray diffraction analysis and transmission electron microscopy (TEM) observation showed its good structural properties; high crystalline quality, high degree of lateral uniformity, well defined interfaces and strong periodicity. Another SL with 100 periods of ZnSe (33Å) / GaAs (25Å), which have smaller layer thickness and much larger number of periods compared with the SL mentioned above, could be also fabricated and the crystalline quality was found to be excellent by X-ray diffraction measurement.