Rare-earth Doped GaN - An Innovative Path Toward Area-scalable Solid- state High Energy Lasers Without Thermal Distortion (2nd year)

摘要

In situ neodymium (Nd) doping of gallium nitride (GaN) and aluminum nitride (AlN) by plasma-assisted molecular beam epitaxy (PA-MBE) has been demonstrated for the first time. For GaN, Nd doping as high as approximately 8 at.% has been demonstrated, with no evidence of phase segregation identified by x-ray diffraction (XRD) for Nd up to approximately 1 at.%. The strongest roomtemperature luminescence was observed for a doping level between 0.1-1 at.%. The Stark energy levels of the three characteristic Nd emission multiplets were resolved by photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopy. The enhanced substitutional doping at the gallium (Ga) site and low optical loss in waveguide structures suggests that GaN:Nd may have significant potential for use in simple, area-scalable, room-temperature, diode-pumped solidstate high energy lasers (HELs). Next-generation devices may be able to take advantage of the improved thermal conductivity of an AlN host.