Optical gap energy of eletrodeposited ZnO nanorods and its non-radiative recombination

Abstract

In order to achieve the applications of the ZnO nanorod arrays in the novel nanostructured solar cells, it is necessary to tailor and control the nanorods' morphological, optical and electrical properties. The ZnO nanorods arrays were fabricated by electrodeposition. The physical properties such as the diameter, density, distance, optical band gap energy, near band emission and Stokes shift can be adjusted by the use of In(NO3)3 and NH4NO3.The characterizations such as scanning electron microscopy, X-ray diffraction spectrometer and photoluminescence were used to measure the samples' morphology, crystal property, transmission and reflection and photoluminescence properties. According to the measurement results, the ZnO nanorod arrays' density is reduced to 5.9×109 cm-2 and the distance between nanorods is enlarged to 108 nm by using NH4NO3. The nanorods' diameter is decreased to 22 nm. The use of In(NO3)3 leads to the blue shift of the ZnO nanorods' optical band gap energy by 100 meV. The optical band gap energy is further tailored between 3.41 eV and 3.55 eV by using NH4NO3. The ZnO nanorods' Stokes shift can be decreased to 19 meV by using NH4NO3, resulting in the effective suppression of the non-radiative recombination.

Keywords

• zno
• ammonium nitrate
• indium nitrate
• electrodeposition
• optical band gap
• non-radiative recombination