MS24-P05 Structural and optical characteristics of non-polar ZnO epitaxial films grown by radio-frequency magnetron sputtering Chia-Hung Hsu (Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan) Bi-Hsuan Lin (Experimental Facility Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan) Wei-Rein Liu (Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan) Wen-Feng Hsieh (Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan)email: chsu@nsrrc.org.twZnO is recognized as an important wide band gap semiconductor material for its applications in UV and blue spectral range devices such as light emitting diodes (LEDs), laser diodes (LDs), and photodetectors. The non-centrosymmetric characteristics of its wurtzite structure gives rise to piezoelectric and spontaneous polarizations along the c-axis. The polarization across the interface of c-axis oriented quantum well structures results in the undesired effects such as quantum confined Stark effect and deteriorates the electronic and optical properties of devices. Therefore, many efforts have been put to grow and to characterize non-polar ZnO epitaxial films.
High-quality non-polar a-plane and m-plane ZnO epitaxial films were grown on r-plane and m-plane sapphire substrates, respectively, by radio-frequency magnetron sputtering. The structural characteristics, including strain and structural defects, of both non-polar ZnO films were studied by X-ray diffraction and transmission electron microscopy (TEM). Surface morphology and roughness of the ZnO samples was investigated by atomic force microscopy (AFM). The anisotropic optical properties of the non-polar ZnO films characterized by polarization-dependent photoluminescence (PL) are correlated with its structural features.
References:

Lin, B. H. et al. (2012). ACS Appl. Mater. Interfaces 4, 5333-5337
Keywords: non-polar ZnO, strain, structural defects