To design a solar cell with a high efficiency it is necessary to convert the visible photons emitted from the sun into electrical carriers and to quickly spatially separate them before they can recombine. A possible way to succeed is to combine the physical properties of ZnTe and CdSe, two II‐VI semiconductors which absorb well the visible light. Many layers of those materials with a few nanometres in thickness can be grown on top of each other thanks to molecular beam epitaxy. The resulting superlattice can be employed as a solar cell with the physical properties of both ZnTe and CdSe. However, during the growth of the interfaces between the layers several scenarios can happen. First, atoms building the respective layers could remain on their side of the interfaces. The resulting interfaces are sharp and either made of a ZnSe or a CdTe monolayer. The other possibility is the diffusion of the atoms into the other layer. The resulting interfaces are wider and most likely made of an alloy of the four chemical species. Transmission electron microscopy is a characterization technique which obtains images of materials with atomic resolution. From the position of the atomic columns on the images, it is possible to deduce their chemical nature. This approach has been combined with atom probe tomography which allows the reconstruction of a small volume of a few tens of nanometre in 3D atom by atom after they have been evaporated from a sharp needle. From these techniques we reported the atomic structure of a ZnTe/CdSe superlattice in which we specifically tried to grow sharp CdTe interfaces. The observation revealed that both interfaces are composed of ZnSe. Pure and sharp CdTe interfaces are not observed and Zn atoms are also visible in the CdSe layer. This information is helpful to find growth conditions suitable to design superlattices that can be employed as solar cells.