Optical properties of δ-doped ZnSe:Te grown by molecular beam epitaxy:: The role of tellurium -: art. no. 155205

We have studied the optical properties of the delta -doped ZnSe:Te system using photoluminescence (PL) and x-ray and Raman scattering. Two different types of sample were investigated, (1) with a single delta layer and (2) with three adjacent delta layers separated by undoped layers. All of these samples are of reasonable crystalline quality and have the symmetry of the host ZnSe lattice as determined by x-ray and Raman scattering. The PL from each sample is very similar to the PL from bulk Zn-Se-Te solutions at low Te concentrations. The PL from the single-delta -doped material shows emission relatively close to the band edge which we attribute partly to Te-2 clusters (nearest-neighbor pairs) and partly to non-nearest pairs. This PL changes with storage time, from which we conclude that the nearest-neighbor pairs are more stable than non-nearest-neighbor pairs. The triple-delta -doped material also shows a deeper PL feature, with a peak at about 2.48 eV, which we attribute to Te-n greater than or equal to3 clusters as well as to corresponding non-nearest-neighbors pairs.