In conventional semiconductor quantum heterostructures such as quantum wells based on GaAs or InAs that power today’s high-speed transistors  in  our  cell  phones,  or  the  lasers  in  fiber-optic communication systems that carry our emails across the globe, it is necessary to precisely tune the energy of the electrons by quantum confinement. The range of tunability is restricted by the materials in use by the energy band offsets in the wells and barriers.  

Driven by the MGI philosophy of theory-guided materials discovery, this DMREF proposal has enabled the joint Michigan-Cornell-Stanford team to demonstrate quantum heterostructures where the tunability of electron energy states in a quantum heterostructures is pushed to record high levels.  This is enabled by an aluminum nitride barrier layer that has an extremely large bandgap, and a quantum well of gallium  nitride,  which  is  currently  used  for  the  LEDs  in  our  cell phones.  This structure pushes the photon emission energy from near visible to the deep-UV, to a spectral range that becomes useful for water treatment, medical sterilization, and biophotonics.