Published online by Cambridge University Press: 21 February 2011
Recent progress in metalorganic chemical vapor deposition (MOCVD) of wide bandgap II-VI materials, especially of ZnSe, ZnS and their alloys, is discussed with emphasis on the general principles for obtaining uniform and high quality epitaxial layers and the current major issue of impurity doping for achieving conductivity control. The surface morphology and crystalline quality can be improved by a suitable choice of source materials and by lattice-matching the epitaxial layer to the substrate. By using appropriate sources, high conductivity n-type epitaxial layers of ZnSe and ZnS doped with impurities from group HI and VII of the periodic table have been successfully grown by low temperature MOCVD. We have also grown p-type ZnSe layers with carrier concentration ranging from low 1016 to high 1017 cm−3 using Li3N as the dopant. Extensive studies are now focussed on the better p-type control. High purity source materials, appropriate p-type dopants and low temperature growth are important keys.