Quantitative Measurement of the Electron and Hole Mobility−Lifetime Products in Semiconductor Nanowires

The mobility−lifetime products (μτ) for electrons and holes in CdS nanowires were quantitatively determined by scanning photocurrent microscopy of devices with ohmic contacts. Ohmic contacts were fabricated by ion bombardment of the contact regions. By analyzing the spatial profiles of the local photoconductivity maps, we determined that electron transport (μ e τ e ≈ 5 × 10 -7 cm 2 /V) was more efficient than hole transport (μ h τ h ≈ 10 -7 cm 2 /V). The results demonstrate that photocurrent mapping can provide quantitative insight into intrinsic carrier transport properties of semiconductor nanostructures.