Photoluminescence of PbS quantum dots on semi-insulating GaAs

We studied the emission properties of colloidal PbS quantum dots (QDs) (5.3 nm) dispersed on semi-insulating GaAs in the temperature range of 5-300 K by employing Fourier transform infrared photoluminescence spectroscopy. The results reveal that the PbS QDs alter and notably enhance the emission features of the GaAs substrate itself. The dependence of the QD emission peak position on temperature is modeled equivalently well with the well-known empirical Varshni equation and with a relation based on thermodynamics. The work reveals that emission properties of PbS QDs do not follow predictably general rules but are determined sensitively by the preparation method and substrate used. © 2010 American Institute of Physics.