Synthesis and characterization of N-doped zinc oxide nanotetrapods

Abstract

Nitrogen-doped (N-doped) self-assembled nanotetrapods ZnO were synthesized via chemical vapor deposition process using N₂O as a dopant source via vapor-solid (VS) growth. The decomposition of N₂O gas giving NO and NO₂ during the synthesis provided successful N-doping of the sample. All samples (N-doped and undoped) were characterized by XRD, SEM, TEM, EDX, photoluminescence (PL), Fourier transform infrared (FT-IR), and diffuse reflection spectra. After nitrogen-doping process, N-doped ZnO samples show the change in structural and optical properties. The detailed structure and the growth mechanism of individual ZnO tetrapod is characterized by TEM and SEM investigations. The TEM study gives the direct assumption about the formation of zincblende (sphalerite) structure on the initial stage of growth of N-doped tetrapods. Besides, SEM observation indicated that tetrapods have perfect tetrahedral symmetry. N-Doped ZnO samples exhibit a broad orange-red PL emission band, peaking near 2.1 eV, in good agreement with the deep-acceptor model for the nitrogen impurity. An IR absorption peak at 3146 cm^–1 at room temperature was observed for N-doped sample. This peak has been unambiguously assigned to N–H complex.