Synthesis and optical properties of zinc oxide nanoparticles grown on Sn-coated silicon substrate by thermal evaporation method

摘要

The Zinc oxide (ZnO) nanoparticles have been grown on n type silicon substrate using tin (Sn) metal as seed layer by a low cost thermal evaporation method. SEM images show that the ZnO nanoparticles have been uniformely grown on the whole surface relatively perpendicular to the substrate. The Photoluminescence (PL) spectrum consists of strong UV emission at wavelength of 355 nm along with a broad near band edge (NBE) emission covering a wide range of wavelength from 370 to 550 nm. This broadening region exhibits blue, violet and green emission due to the presence of different native defects such as zinc interstitial (Zn_i, oxygen vacancy (V_O) and oxygen interstitial (O_i) in the band gap of ZnO. Raman spectroscopy shows the existence of E_2 mode at 437 cm~(-1) which confirms the pure wurtzite hexagonal phase of ZnO. Therefore, the optical and structural properties of as-grown ZnO nanoparticles could be well explored for blue-violet light emitting diodes (LEDs), photo detectors and gas sensing applications.