Optical properties of Wurtzite Zn1-xCdxO films grown by remote-plasma-enhanced metalorganic chemical vapor deposition

Zn1-xCdxO films were grown on a-plane (11 (2) over bar0) sapphires by remote-plasma-enhanced metalorganic chemical vapor deposition (RPE-MOCVD). The growth temperature, the group-II flow ratio R, and RF power are important parameters for the growth of Zn1-xCdxO films by RPE-MOCVD. R is defined as the molar function of [DMCd/(DEZn + DMCd)]. We discuss typical growth features associated with RPE-MOCVD and the refractive indices of wurtzite-type films. The band gap energy of Zn1-xCdxO grown at 350 degrees C can be controlled from 3.3 down to 1.8 eV. The refractive index is measured by ellipsometry at 1.96 eV and is found to vary from 2.07 to 2.78.