Colloidal CdTe/HgTe quantum dots with high photoluminescence quantum efficiency at room temperature

We have used an aqueous colloidal growth technique to form hybrid CdTe/HgTe quantum dots with a broad, strong fluorescence in the infrared (800-1200 n m). The quantum efficiency is high, around 44%, when pumped in the visible (488 nm), and the excited state lifetime is around 130 ns, making the mater ial interesting as an optical amplifier medium. Using a pump-probe experime nt, we have demonstrated weak optical amplification in a dilute aqueous sus pension of CdTe/HgTe dots in the short wavelength wing of the emission spec trum at 808 nm. (C) 1999 American Institute of Physics. [S0003-6951(99)0013 8-2].