4 p.m. - 5 p.m. Location: SLC 1.102
Dr. Joseph Ngai (UT Arlington)
Heterojunctions between semiconductors and oxides form the foundation to field-effect transistors that have revolutionized information processing. However, their principal functionality remains as capacitors within the metal-insulator-semiconductor (MIS) paradigm. Advances in epitaxial growth now enable single-crystalline multifunctional oxides to be grown directly on semiconductors, opening a pathway to elevate the semiconductor-oxide heterojunction beyond the MIS paradigm. In this talk I will review the structural and electronic properties of multifunctional oxides and their epitaxial integration on semiconductors. In particular, we will discuss our recent efforts in achieving charge transfer and the formation of built-in potentials across SrNb_xTi_(1-x)O_(3-δ)/Si(001) heterojunctions. We will discuss how electrical transport measurements combined with hard x-ray photoelectron measurements enable built-in fields to be spatially mapped across heterojunctions. Control of charge transfer and built-in fields could enable hybrid semiconductor-oxide pn-junctions, isotype junctions etc., to be realized; such heterojunctions could address emerging challenges in energy harvesting and information technology.