Distributed Bragg reflector made of CdSe and ZnTe

Distributed Bragg reflector (DBR) is a multilayer periodic structure with a high eflectance of the light due to the constructive interferences.Applications of DBRs include lasers, solar cells, photo-detectors, microcavities, and various photonic structures. DBRs can be made of II–VI semiconductors, however, this requires using hygroscopic Mg compounds which easily degrades in outdoor conditions. Here we present a new kind of II–VI semiconductor DBR free of hygroscopic Mg, made of only binary, almost lattice matched layers of ZnTe and CdSe. Our structure is grown using molecular beam epitaxy, and it consists of 30 DBR pairs. Due to the energy gap of CdSe, the high reflectivity of our DBR can be achieved for wavelength above 700 nm, in particular for telecom wavelengths. Analysis of reflectivity spectra allows us the precise determination of spectral dependence of the refractive index of CdSe in zinc-blende structure.