Theoretical Research Of SrTiO₃ Ferroelectric Thin Films Initial Growth And Adsorption On Gan(0001) Surface

The adsorption of SrTiO₃ on GaN(0001) surface has a very broad application prospects on the integration phase shifters, filters, resonators, field-effect transistors and other integrated deVice. On the experiment, although we have directly grown the SrTiO₃ films on GaN(0001) surface ,that it was a difficult to obtain high quality SrTiO₃ films. Because of the lack of effective experimental research, the theoretical calculation and computer simulation is an important way to explore the SrTiO₃ / GaN thin film.When the SrTiO₃ thin film deposit in a vacuum , the main component of the SrTiO₃ is Sr-O, Ti-O particles . Considering the adsorption of different orientation, we construct the variety of adsorption model of SrO, TiO₂ on the perfect GaN (0001) (2×2) surface. In the virtual experiment temperature, we can acquire the adsorption process and analyze adsorption energy , bonding processing, adsorption orientation, surface , interface structure and surface state density by using the dynamics calculation. The results indicate that Ti atom is adsorbed in fcc site or in hcp site, and two O atoms are combined with two Ga atoms on GaN surface after adsorption, respectively. The chemical bonding of Ga—O shows a covalent feature and chemical bonding energy achieved 7.93eV. The O-O line directions lie along the GaN [11-20] directions, in accordance with experimental reports of (100) [001] TiO₂ // (0001) [11-20] GaN.Comparison of SrO, TiO₂ adsorption process, we know the adsorption energy of TiO₂ greater than the adsorption energy of SrO . The results indicate that the TiO₂ is conducive to adsorb on the perfect GaN (0001) (2×2) surface.