Strong electro-optic effect in Mg incorporated ZnO thin films

a-axis oriented ZnMgO epitaxial thin films with a strong linear electro-optic (EO) effect were developed by radio frequency magnetron sputtering. The Mg incorporation into ZnO thin films not only obviously increases the transmittance at the wavelength range of 400-800 nm but also reduces the leakage current by 3-6 orders of magnitude. Furthermore, with the increase in the Mg content, the linear EO response enhances significantly. In particular, the derived effective EO coefficient r(c) of the Zn0.72Mg0.28O thin film is (7.6 & PLUSMN; 0.2) pm/V, which is over three times larger than the reported values for ZnO-based thin films and over twice larger than that of ZnO single crystals. The results and discussion conclude that an enhanced intrinsic contribution can be responsible for the increase in r(c) with Mg incorporation. These findings open the way for the ZnO-based thin films to EO devices in optical communication and optical interconnects. Published under an exclusive license by Laser Institute of America.

Automated summary

A-axis oriented ZnMgO epitaxial thin films were developed with a strong linear electro-optic effect. The incorporation of Mg into ZnO films not only increases transmittance but also reduces leakage current. Furthermore, the linear electro-optic response is significantly enhanced with the increase in Mg content.