Optical properties and bridge photodetector integration of lead sulfide nanowires

Abstract

We studied optical properties and photocurrent characteristics of PbS nanowires grown by chemical vapor deposition. Distinct bandedge photoluminescence (PL) emission was observed in the mid-infrared spectral range and the quantum confinement effect estimated from the PL peak energy was within 40 meV, consistent with the average diameter of the nanowire (similar to 70 nm) being significantly larger than the exciton Bohr radius (similar to 18 nm). We also demonstrated interdigit photo detectors making use of these PbS nanowires suspended between two pre-patterned Ti electrodes, where Ti also acted as metal catalyst for the nanowire growth. The threshold wavelength of the photocurrent was found to be similar to 3 mu m at room temperature.