Behavior of dual ion beam sputtered MgZnO thin films for different oxygen partial pressure

Abstract

Mg-doped ZnO (MgZnO) films were grown on p-Si (001) substrates by dual ion beam sputtering deposition system at a constant growth temperature of 600 °C for different oxygen partial pressure. The impact of oxygen partial pressure on the structural, electrical, elemental and morphological properties was thoroughly investigated. X-ray diffraction (XRD) spectra revealed that the deposited MgZnO films were polycrystalline in nature with preferred (002) crystal orientation. The peak of MgZnO (101) plane was reduced significantly as oxygen partial pressure was increased and disappeared completely at 80 and 100 % O2. The maximum electron concentration was evaluated to be 5.79 × 1018 cm−3 with resistivity of 0.116 Ω cm and electron mobility of 9.306 cm2/V s at room temperature, for MgZnO film grown with 20 % O2. Raman spectra shows a broad peak at 434 cm−1 corresponded to E 2 high phonons mode of MgZnO wurtzite structure. The peak at 560 cm−1 corresponded to the E1 (LO) mode and was associated with oxygen deficiency in MgZnO films. Raman intensity at 560 cm−1 reduced, on increasing oxygen partial pressure. A correlation between structural, electrical, elemental and morphological properties with oxygen partial pressure was also established.