Molecular-beam-epitaxy-grown ZnSe/ZnTe high-reflectivity distributed Bragg reflectors
A series of distributed Bragg reflectors (DBRs) with different numbers of periods were fabricated by molecular beam epitaxy using ZnSe and ZnTe layers grown on GaAs substrates. The ZnSe/ZnTe combination manifests over 7% lattice mismatch, which leads to a deterioration of multilayer stacks with large numbers of periods. However, even with the deposition of only eight periods we have obtained ZnSe/ZnTe DBR structures which yield reflectivities in excess of 85%. Furthermore, these DBRs show wide stop-bands - an additional advantage of using the ZnSe/ZnTe combination. By varying the number of periods in these structures, we have also studied how the reflectivity changes with the number of periods in this materials combination. The reflectivity obtained by depositing four ZnSe/ZnTe periods was 66.5%, while by depositing 15 periods we obtained 91% reflectivity.