Mg Doping Effect on Nanoscale Crystallization and Band Gap of Sol-Gel Derived MgxZn1-xO (x=0-1) Alloys

A series of MgxZn1-xO (x = 0-1) alloyed powders with different Mg concentrations were crystallized by sol gel technique. Their morphological variation with increased Mg content was investigated by scanning electron microscopy (SEM). We found that the introduction of Mg2+ ions into ZnO matrix had significant influence on the crystallinity of highly Mg-incorporated alloys. In particular, different packing density and the interagglomeration of the nanoparticles give rise to textural nanosized pores in the pure ZnO spherical particles and pure MgO hollow shells. UV-visible (UV-Vis) absorption spectra indicate that Mg doping significantly increases the band gap of MgxZn1-xO alloys. Different alloyed crystals were also annealed in the range of 600-1000 degrees C to investigate their thermal stability and temperature-dependent optical properties, which indicates that the Mg concentration in the as-obtained alloys is a function of annealing temperature, thereby facilely tuning the band gap. These results suggest that MgxZn1-xO alloys have potential applications in a variety of optoelectronic devices.