Magnetic Doping of III-V Nitrides and Novel Room Temperature Sensing Applications

摘要

Electronic doping of III-V nitride semiconductors is the basis of many optoelectronic devices, including bright, long lasting, light emitting diodes and lasers. Doping of this material system with optically active dopants has increasing potential for full color displays and optical storage. Another important use of the III-V nitrides is the doping with magnetic atoms to form dilute magnetic semiconductors (DMS). Recent experimental results have shown that DMS thin films, such as GaN:Mn, GaN:Fe, and GaN:Co, possess ferromagnetic ordering with a Curie temperature T_C > 300K. These room temperature DMS films can be incorporated in multilayer, heterojunction structures to exploit the property of electron spin for room temperature sensing, logic, and switching. For practical applications, "spintronic" devices must be based upon DMS materials that have a ferromagnetic transition temperature at or above room temperature. In this talk, aspects of ion implantation of magnetic elements into III-V nitride films will be discussed along with structural and magnetic characterization. Recent data concerning the implantation of AlN thin films with Mn, Co, and Cr ions and resultant ferromagnetic ordering will be presented. Extension of these studies to form practical spintronic devices will be treated. In particular, a novel concept for room temperature sensing of chemical and biological agents will be presented. This concept provides a method for achieving high specificity and high sensitivity in micro-chip sensor suites.