Upcoming Events

Quantum Band Engineering with New Materials for Infrared Light Emission

October 25, 2012 2:00PM to 3:00PM
Presenter 
Oana Malis, Purdue University
Location 
Building 440, Room A105-106
Type 
Colloquium
Series 
CNM Nanoscience Colloquium
Abstract:
Quantum confinement in the conduction band of semiconductor heterostructures brings about fascinating optical properties in the infrared range of the spectrum. Research on intersubband transitions inrecent years has resulted in fundamental discoveries that eventually triggered practical device applications. Our goal is to creatively exploit the uniqueproperties of nano-structured III-nitride materials for novel light emitters and detectors in the currently under-developed near- and far-infrared ranges. Due to large electron effective mass, the nitride intersubband materials require the ability to fine-tune the atomic structure at an unprecedented sub-nanometer level.

I will describe our efforts to understand, model, and control the effects of the nanostructure on optical properties and verticaltransport in nitride heterostructures to realize the theoretical potential of this material system. Special attention will be given to the relationship between growth, structure, and optical properties in lattice-matched AlInN/GaN heterostructures. We also report the first observation of exactly reproducible low-temperature negative differential resistance in c-plane resonant tunneling diodes on low-defect quasi-bulk GaN substrates.