Optical properties of colloidal InGaP/ZnS core/shell nanocrystals

The energy band gap (E-g) of colloidal InGaP/ZnS core/shell nanocrystals is investigated by using the optical absorption and the photoluminescence techniques. While the photoluminescence spectra exhibit a strong emission, the optical absorption spectra show a very weak excitonic absorption. From E-g values estimated from the optical absorption spectra, the In composition is calculated to be on the order of 45%-48%. The estimated In mole fraction suggests that InGaP is still a direct band gap semiconductor. The energy band gap is recorded as a function of temperature from which the Debye temperature and the average phonon energy were extracted. The energy band gap (E-g) of colloidal InGaP/ZnS core/shell nanocrystals is investigated by using the optical absorption and the photoluminescence techniques. While the photoluminescence spectra exhibit a strong emission, the optical absorption spectra show a very weak excitonic absorption. From Eg values estimated from the optical absorption spectra, the In composition is calculated to be on the order of 45%-48%. The estimated In mole fraction suggests that InGaP is still a direct band gap semiconductor. The energy band gap is recorded as a function of temperature from which the Debye temperature and the average phonon energy were extracted. (c) 2006 American Institute of Physics.