Another day, another paper from Suresh Thapa! This paper in ACS Applied Materials and Interfaces comes through a collaboration with Boris Kiefer and Sharad Mahatara at New Mexico State University where we have combined theory and experiment to examine the BaSnO3/SrNbO3 interface as a 2D electronic system. Sharad and Suresh deserve credit for getting this theory/experiment going and we’re happy to have built a new collaboration with Boris’ group. Thanks also to Hanjong Paik for the growth of the BaSnO3 films through the Cornell PARADIM user facility.
BaSnO3 is a high mobility, wide bandgap semiconductor that is promising for high electron mobility transistors and other devices. However, it is hard to modulation dope across the interface because of the low effective mass and band filling of the Sn 5s orbitals. Enter SrNbO3, which has low electron affinity and will readily donate electrons across an interface to BaSnO3. Using MBE to grow these heterostructures and in situ XPS to measure charge transfer, we’ve estimated that we can get more than 1014 electrons/cm2 into BaSnO3, which is more than a 10x improvement over past materials work with other donor materials. DFT modeling predicted carrier concentrations quite well. It’s a very promising first step towards engineering higher carrier concentrations in stannates with a lot more work to come.
This work was supported by our Air Force Office of Scientific Research (AFOSR) Young Investigator project and Suresh’s Alabama EPSCOR Graduate Research Scholars fellowship.