Nonpolar ZnO thin films: growth-related structural and optical properties (2014)
Total project period 2014
Principal investigators from three sides:
- Latvia: Laima Trinkler, Institute of Solid State physics, University of Latvia
- Lithuania: Ramunas Nedzinskas, Optoelectronics Department, Center for Physical Sciences and technology
- Taiwan: Mitch Chou, Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung, Taiwan
The Project is devoted to the advanced growth of nonpolar ZnO epitaxial films, which have a great potential for development of multiple quantum well (MQW) devices. In this project ZnO layers are grown on LiGaO2 - a promising substrate, which provides both the smallest mismatch and the nonpolar orientation and thus may lead to fabrication of high quality nonpolar ZnO epitaxial films.
To reach this goal, cumulative efforts of three complimentary research teams are focused on growth of ZnO layers using chemical vapour deposition (CVD) and molecular beam epitaxy (MBE) under varied synthesis conditions and further structural, optical and photoelectrical properties.
During the first year of the Project the research teams have achieved the sufficient progress in implementation of the project tasks. Taiwanese group has grown a number of epilayer and quantum well (QW) ZnO/LiGaO2 samples using MBE method. The samples grown were analysed by means of structure analysis and cathodoluminescence. Latvian group has characterised the MBE-grown ZnO/LiGaO2 samples using the methods of photoluminescence and polarised luminescence at low temperatures. Lithuanian group has studied the previously received ZnO/LiGaO2 samples produced in Taiwan by the method of chemical vapour deposition (CVD). For characterization of the samples the methods of modulated reflectance, spectroscopic ellipsometry and optoelectrical characterization using time resolved optical “pump-probe” techniques were used.
Participants of the project from Latvia, Lithuania and Taiwan met altogether to share and discuss experimental data and to present results of the joint research at the Project Meeting and International symposium RCBJSF-2014-FMNT held in Riga (September 2014). Altogether 8 report were presented at the Project meeting. The results obtained in the first year of the project were summarised in 1 oral and 2 poster presentations at RCBJSF-2014-FMNT.