Anneal in H 2 :N 2

1. EPR detected passivation of the Mg acceptor Mary Ellen Zvanut, University of Alabama at Birmingham, DMR 1006163 The addition of Mg to GaN creates a p-type semiconductor typically used in blue and white-light LED’s. Passivation of Mg acceptor Anneal in H2:N2 N N H Mg H Mg ● The conductivity achieved with present Mg doping is limited under standard growth methods, but recently introduced metal modulation epitaxy enables this limit to be exceeded by about a factor of five. ● Hydrogen, omnipresent during processing, electrically quenches (passivates) the conductivity, and the EPR signal may be used to monitor the passivation process. N N N N N N EPR Results Mg unpassivated passivated We show (right) that heavily Mg doped GaN films are more susceptible to hydrogen passivation than the conventionally Mg doped films. Therefore, care must be taken when processing. Dependence of the EPR intensity (shown above) on anneal temperature for GaN films doped with different amounts of Mg

2. The kinetics of Mg-H interaction in AlxGa1-xN:MgMary Ellen Zvanut, University of Alabama at Birmingham, DMR 1006163 The project has provided research experience and education to undergraduates in the following ways: Undergraduate Research: One undergraduate (pictured left) has extended the previously described passivation studies to AlGaN, a semiconductor essential to future lighting needs. He will present his work at a meeting of the Southeast American Physical Society in October, 2011. Education: The PI, Mary Ellen Zvanut, presented an overview of LED’s in a presentation entitled “LED’s: will they light up your life?” to the UAB Society of Physics Students and to the summer 2011 REU students. Undergraduate physics major, UstunSunay, prepares the furnace for a H2:N2 anneal.