Enhanced photoresponse in ZnO nanowires decorated with CdTe quantum dot

The photoresponse of ZnO nanowires irradiated with photons having energies below the band gap of ZnO (3.4eV) was studied before and after deposition of CdTe quantum dots via a pulsed electron-beam technique. The small amount of deposited CdTe did not increase the dark current of the samples. However, a substantial increase in the steady state photocurrent was observed after CdTe deposition suggesting a clear photosensitization effect. Results revealed that CdTe influences the photoconductivity transients of ZnO by minimizing its interaction with oxygen in air as well as providing additional traps that serve to increase the photocurrent time constant.