Defects altered n/p-type Fe/Ga modified ZnO for photo-sensing applications

Abstract

Sol-gel prepared Fe/Ga co-doped ZnO, i.e., Zn0.9844(Fe1−xGax)0.0156 nanoparticles, with varying proportions of Fe/Ga, have been investigated. Individual Fe or Ga modified ZnO is well studied in reports. Structural properties, especially lattice defects and disorder, have not been correlated well enough to the electronic properties and related applicability. Fe-doping is reported to reduce conduction, while Ga-doping enhances the same. To understand the structural changes and how it is related to the modifications in the electronic properties, an attempt is being made to co-doped Fe/Ga in the ZnO lattice so that an understanding of the complex competition of these opposite natures can be studied. Sol-gel prepared Fe/Ga modified ZnO with P63mc space group is investigated for this purpose. The structural, defects and electronic behavior of modified and pristine ZnO have been detailed using: X-ray diffraction, Raman spectroscopy, UV–vis/PL spectroscopy and Hall-effect measurements. Changes in the electronic behavior i.e., conductivity in light ON and OFF conditions is also well studied and correlated with defects. A theoretical analysis of the same was performed using the electron localization function of the system which reveals a weaker electron cloud around Fe but a stronger around Ga as compared to Zn, thereby resisting and aiding the conduction process in Fe-doped and Ga-doped samples. The mobility, carrier concentration, and Hall coefficient parameters are modified along with the modified native defects of ZnO.