Schottky barrier formed by network of screw dislocations in SrTiO3 -: art. no. 162105

A network of screw dislocations was artificially created in SrTiO3, and characterized by transmission electron microscopy (TEM). Slight expansion of the dislocation core was observed by TEM. The composition of the dislocation core was quantified by electron energy loss spectroscopy, which reveals a 13 +/- 5% Ti/O ratio increase but no Sr/Ti ratio change in the core, demonstrating an oxygen deficiency or oxygen vacancy surplus in the dislocation core. The vacancy surplus was estimated to be about one vacancy every unit cell along the core. The dislocation core is positively charged; therefore, oxygen vacancies and holes are expelled from the dislocation network, forming a double Schottky barrier, which blocks charge carrier transports across the network. The Schottky barrier height at T=823 K and P-O2=2 Pa was determined to be similar to 0.48 V. (C) 2005 American Institute of Physics.