Determination of Valance Band Offset in Sr2TiO4/SrTiO3 heterostructures
EMSL Project ID
2465
Abstract
The ultimate goal of this research is the creation of a 2D electron gas in heterostructures comprised of members of the Sr-Ti-O Ruddlesden Popper homologous series. An understanding of the fundamental properties of the individual members of this series is essential for engineering a possible 2DEG heterostrucuture. We would like to use the XPS system on MBE #1 at PNNL for an investigation of the band offsets between the end members of this series, Sr2TiO4 and SrTiO3. Four epitaxial heterostructures have been grown by molecular beam epitaxy at Penn State for this study. These Sr2TiO4 films are grown on SrTiO3 substrates and have a thickness of 150, 12, 24, and 36 angstroms. This series of samples should allow us to compare the spectra of a SrTiO3/Sr2TiO4 heterostructure and the summed spectra of Sr2TiO4 and SrTiO3, as well as to correct for absorption and thickness effects. These spectra should lead to an accurate determination of the valance band offset between SrTiO3 and Sr2TiO4. This value, combined with ellipsometry studies being performed at Penn State to determine the bandgap of Sr2TiO4 should allow both the valance and conduction band offsets between SrTiO3 and Sr2TiO4 to be determined.
Project Details
Project type
Exploratory Research
Start Date
2002-05-20
End Date
2005-05-22
Status
Closed
Released Data Link
Team
Principal Investigator