Low-Temperature Chemical Growth of ZnO Nanorods with Enhanced UV Emission on Plastic Substrates

In this paper we report ZnO nanorods (NRs) grown by a two step chemical bath deposition method at temperature down to 50 degrees C. The structural and optical properties of the as deposited ZnO NRs grown at 50 degrees C, 75 degrees C, and 95 degrees C, were all investigated and compared using X-ray diffraction and photoluminescence. X-ray diffraction verified that all grown ZnO NRs have a preferential growth orientation along the c-axis and that all samples show the same peaks with the same intensity indicating the same structural quality despite the different growth temperatures. By comparing the PL of the different samples grown at different temperatures, surprisingly the sample grown at the lowest temperature (50 degrees C) exhibit an enhancement in the near band emission intensities by more than three orders of magnitude and a suppressed deep level emission by the same amount. This is explained by the fact that the lower growth temperature did not provide enough energy for native point defects to nucleate.