Double band structure of ZnSe/CdSe/ZnSe quantum dots for photovoltaic devices

The ZnSe/CdSe dot/ZnSe/CdSe dot/ZnSe structure is fabricated with changing irradiation time of Cd-beam. Two PL peaks can be observed at 2.782 and 2.762 eV. The intensity of higher energy peak is intense and has narrow FWHM, and the intensity of lower energy peak is weak and has rather broad FWHM. As the increase of Cd irradiation time, both A-peak and B-peak moved towards lower energy side. When the CdSe layer is thinner than an ideal atomic layer epitaxy proceeds in ALS growth, no SK-CdSe dots can be generated.