Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 17: Poster I

HL 17.35: Poster

Montag, 25. Februar 2008, 16:30–19:00, Poster D

Properties of the crystal lattice and electronic structure of metastable III(N,V) semiconductors — •Martin Güngerich¹, Gerhard Weiser¹, Wolfram Heimbrodt¹, Oleg Rubel¹, Peter J. Klar², Paul Harmer³, Mark P. Jackson³, and Matthew P. Halsall³ — ¹Fachbereich Physik und WZMW, Philipps-Universität, 35032 Marburg, Germany — ²I. Physikalisches Institut, Justus-Liebig-Universität, 35392 Gießen, Germany — ³Department of Electronic and Electrical Engineering, University of Manchester, Manchester M60 1QD, United Kingdom

The incorporation of nitrogen on group-V lattice sites in III-V semiconductors like GaP, GaAs and GaSb leads to substantial changes of the vibrational spectrum and the electronic structure compared to the host crystals. Our work gives an overview of the interesting physical properties of such metastable compounds with N concentrations up to a few percent. We show that local vibrational modes (LVMs) of the N atoms are a common feature in these alloys. The pressure-dependent frequency shifts of the LVMs are used to investigate the micro-mechanical properties of the N-Ga bonds. It is shown that the electronic structure in both Ga(N,P) and Ga(N,As) is governed by an interplay between the spatial distribution of the N impurities themselves and the coupling of their localized states to the host conduction bands. Correlations between different local N environments and the respective changes of the global electronic structure are studied on hydrogenated ternary Ga(N,As)/Ga(N,P) as well as on quaternary (Al,Ga)(N,As) crystals which exhibit disorder on the nearest-neighbour shells of the N atoms.