ZnSxSe1-x heteroepitaxial growth on GaP by metalorganic vapor phase epitaxy

In this study, a double heterostructure of ZnSxSe1-x/ZnS0.86Se0.14/GaP has been grown by metalorganic vapor phase epitaxy. There is a transition regio n between the substrate and epilayer. The sulfur concentration on growing s urface is a crucial point for the quality of the following layer. The botto m confinement layer ZnS0.86Se0.14 lattice-matched to GaP substrate shows en ergy gap 3.3 eV with photoluminescence full width at half maximum of 60 meV at 77 K. The active layer ZnS0.42Se0.58 with energy gap 2.98 eV shows phot oluminescence full width at half maximum of only 28 meV at 77 K. There is 3 20 meV energy gap difference that is sufficiently high for carrier confinem ent in double heterostructure. However, the energy gap difference between t he top confinement layer and the active layer is only 139 meV which can not be modulated furthermore by the flow rate ratio of hydrogen selenium and h ydrogen sulfur. It is from the strain between two epilayers. (C) 1999 Elsev ier Science S.A. All rights reserved.