Qualifier

John Elliot Ortmann, UT-Austin

"Physics and Device Applications of MBE-Grown Transition Metal Oxide Multiple Quantum Wells"

2:00pm, RLM 13.202

Abstract: Quantum wells are thin film structures constructed by sandwiching a material with a small band-gap between layers of a larger band-gap material, creating a potential well in the small band-gap material that can confine electrons in one direction.  By introducing electrons into the potential well, one can populate discrete, standing wave electronic states in the well.  Electrons in these states can be modulated by infrared light, allowing for the construction of infrared devices such as infrared photodetectors, frequency doubling devices, and quantum cascade lasers.  Traditionally, quantum wells have been made out of III-V semiconductors such as GaAs, AlGaAs, InGaAs, etc.  Here, I will discuss our work on transition metal oxide quantum wells, made out of thin films of SrTiO3 and LaAlO3.  These structures yield much deeper wells than those found in traditional GaAs-based quantum wells, possibly allowing for the fabrication of devices that operate over a much larger energy range.  I will highlight the structural and optical properties of these heterostructures, paying special attention to experiments demonstrating optically driven transitions between well states.