Spatially-Resolved Photoluminescence Mapping of Single CdS Nanosheets

We present results of spatially-resolved low temperature photoluminescence of single 5 micron wide CdS nanosheets. The sheets, grown by pulsed laser deposition using vapor-phase transport, are uniform in size and shape and exhibit a hexagonal wurtzite structure. The orientation of the c-axis determined by PL polarization analysis and HR TEM varies from sheet to sheet. The spatially-resolved PL reveals spectral variation across the sheet, with A-like excitons at the edges showing a spectral peak at 2.547eV, and B like excitons at the center showing a peak at 2.563eV. Exciton lifetimes of $\sim $200 ps are observed, which are significantly longer than CdS nanowires of identical diameter, but shorter than measured in bulk CdS.