Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 22: GaN: Pr
äparation und Charakterisierung I
HL 22.1: Vortrag
Samstag, 5. März 2005, 10:45–11:00, TU P-N201
Rare earth implantation in GaN - an alternative route to develop integrated, all-nitride light-emitting devices — •Katharina Lorenz1, U. Wahl1, E. Alves1, T. Wojtowicz 2, P. Ruterana2, S. Dalmasso3, E. Nogales3, R.W. Martin3, K.P. O‘Donnell3, S. Ruffenach4, and O. Briot4 — 1Instituto Tecnológico e Nuclear, Sacavém, Portugal — 2SIFCOM, CNRS-ENSICAEN, Caen, France — 3University of Strathclyde, Glasgow, U.K. — 4GES, Université de Montpellier II, France
In the frame of the European research and training network RENiBEl (Rare Earth Doped Nitrides for High Brightness Electroluminescent Emitters) we study the doping of GaN by rare earth implantation. GaN epilayers grown by MOCVD were implanted with Er, Tm and Eu under different implantation conditions (varying fluence, temperature, energy). RBS/channeling was used to monitor the damage evolution in the Ga-sublattice after implantation and annealing and to establish the lattice site location of the implanted ions. The nature of structural defects was studied by transmission electron microscopy and the optical properties of the samples by room temperature cathodoluminescence. The introduced damage could be significantly reduced by implantation at high temperature or by implanting through a thin AlN capping layer. Annealing was necessary for optical activation of the implanted samples. After annealing, sharp rare earth related emissions were observed. The emission intensity is highly dependent on the annealing temperature and best results were achieved for annealing up to 1300∘C using an AlN capping layer to protect the surface from dissociation.