Intraband Luminescence from HgSe/CdS Core/Shell Quantum Dots

HgSe/CdS core/shell CQD are synthesized, and the changes in the optical absorption and luminescence are investigated. While HgSe quantum dots are naturally n-doped after synthesis, both as colloidal solutions and as films, the HgSe/CdS core/shell dots in solution lose the n-doping, as seen from the optical absorption in solution However, n-doping is regained in films, and the intraband luminescence of the films of HgSe/CdS is greater than that of the cores. The shell also vastly improves the stability of the quantum dots films against sintering at 200 degrees C. After annealing at that temperature, the HgSe/CdS films retain a narrow intraband emission and sustain a higher laser. power leading to brighter emission at 5 mu m.