Compositional Optimization of PbCaSSe in PbCaSSe/PbS/PbCaSSe DH structure

In this paper, we investigate the compositional optimization of the Pb1−xCaxS1−ySey (PbCaSSe) used for the cladding layer in the PbCaSSe/PbS/PbCaSSe double-hetero structure. The results of X-ray diffraction and optical transmittance revealed that the crystallinity of the PbCaSSe becomes worse as the compositions of Ca and Se increases, while widening the energy band gap. Thus, improvement of the crystallinity and enlargement of the energy band gap of the PbCaSSe exhibits an opposite tendency with respect to the compositions. The photoluminescence intensity of the DH structure strongly depends on the PbCaSSe cladding layer, compositionally maximizing at x=0.08 and y=0.06 that provides the best trade-off between the crystallinity and the energy band gap.