Highly efficient band‐edge emission from InP quantum dots

High quality InP quantum dots with diameters ranging from 25 to 45 A, have been prepared; these quantum dots (QDs) show high quantum yields for band‐edge photoluminescence (lowest energy HOMO‐LUMO transition). The wavelength of the blue‐shifted band‐edge emission ranges from about 575 to 730 nm depending on QD size. The quantum yield for photoluminescence is 30% at 300 K and 60% at 10 K; the multiexponential decay of this emission exhibits lifetimes ranging from 5 to 50 ns. Deep red‐shifted emission due to trapping of carriers in defect states on the QD surface which exhibits lifetimes above 500 ns, has been eliminated by treating the QDs with a dilute solution of HF or NH4F.