The structural, electrical and optical properties of Mg-doped ZnO with different interstitial Mg concentration

• The energy band gap decreases with the increase of interstitial Mg content from 5.88% to 15.79%.
• The conductivity increases with the increase of interstitial Mg content from 5.88% to 15.79%.
• The MgxZn1-xO (interstitial Mg content x= 20%) is found to be a direct-band-gap semiconductor.
• The light transmittance decreases with the increase of interstitial Mg content from 5.88% to 15.79%.
• The refractive index increases with the increase of interstitial Mg content from 5.88% to 15.79%.

Through first principle calculations, we studied the structural, electronic and optical properties of ZnO doped by interstitial Mg. With the increase of Mg content (x), the derivations of lattice parameters from the wurtzite ZnO become more and more significant. The Mg-doped ZnO with x below 15.79% is found to be n-type semiconductor. The minimum of energy band gap and light transmittance in high energy region (7.5–25 eV) decrease while the conductivity and refractive index increase with increasing x. Further increasing x up to 20%, the Mg-doped ZnO is found to be direct-band-gap semiconductor with great structural derivation from wurtzite phase. The light transmittance increases while the refractive index decreases with the increase of x due to the change of geometry and electronic structure. So, it’s concluded that the electronic and optical properties of ZnO doped by interstitial Mg may be greatly influenced by Mg content.

The minimum of energy gap decreases while the corresponding relative number of electrons into the conduction bands increases when the interstitial Mg content x in Mg-doped ZnO increases (0 ≤ x ≤ 15.79%).Figure optionsDownload as PowerPoint slide