A Quasi-gaseous CdCl2 Treatment of a CdTe/CdS Heterojunction

In order to improve the efficiency of a solar cell device, we performed a CdCl2 treatment on a CdTe/CdS heterojunction grown with a sputtering method. The treatment not only used the conventional solution method where the specimen is dipped in CdCl2-methanol solution directly but also used a quasi-gaseous method where the specimen is exposed to the CdCl2 gas vaporized from a quartz vessel containing the CdCl2-methanol solution. The structural, optical and morphological properties were investigated by the help of the X-Ray diffraction, transmission electron microscopy, scanning electron microscopy and UV-Vis-Nir measurements in order to verify the effectiveness of the quasi-gaseous CdCl2 treatment. When all processes were performed under the same conditions except for the CdCl2 treatment, the quasi-gaseous CdCl2 treatment provided results superior to the aforementioned conventional CdCl2 solution treatment in relation to the physical properties of the CdTe/CdS heterojunction.