Polarized photoluminescence and time-resolved photoluminescence from single CdS nanosheets

Abstract

We have utilized polarized low temperature photoluminescence (PL) to probe the electronic states and structural symmetries of individual CdS nanosheets. High resolution transmission electron microscopy measurements indicate highly crystalline material with different nanosheets exhibiting significant variations of the direction of the c axis, which are consistent with polarization measurements of PL from single CdS nanosheets. The quality of the nanosheets is reflected in measurements of exciton lifetimes of similar to 200 ps, a value significantly longer than observed for CdS nanowires whose diameter is the same as the thickness of these nanosheets, but shorter than that observed in bulk crystals.