Photoluminescence and field emission properties of ZnS:Mn nanoparticles synthesized by rf-magnetron sputtering technique

Abstract

Nanoparticles of ZnS:Mn have been grown by radio frequency magnetron sputtering technique on glass and Si substrates at a substrate temperature 300K. X-ray diffraction patterns and selected area electron diffraction patterns confirmed the nanocrystalline cubic ZnS phase formation. TEM micrographs of the films revealed the manifestation of ZnS:Mn nanoparticles with an average size ∼6nm. UV–Vis–NIR spectrophotometric measurement showed that the films are highly transparent (∼90%) in the wavelength range 400–2600nm. From the measurements of transmittance spectra of the films the direct allowed bandgap values have been calculated and they lie in the range 3.89–4.12eV. The bandgap decreased with the increase of Mn concentration in the films. The Mn concentrations in the films have been varied from 0% to 8.9% and was measured by energy dispersive X-ray analysis. The photoluminescence of the Mn doped ZnS nanoparticles was measured. The intensity of the PL peaks at first increased with the increase of Mn concentration in the films up to 3.8% of Mn doping and at a Mn concentration higher than this, the intensity of PL peak decreased. Nanocrystalline ZnS:Mn showed good field emission property with a turn on field lying in the range 5.26–6.78V/μm for a variation of anode to sample distance from 60μm to 100μm.