Münster 1997 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 40: Poster III

HL 40.99: Poster

Freitag, 21. März 1997, 11:00–14:00, Z

Cathodoluminescence study of GaN epilayers on (100) GaAs — •C. Wang, D.J. As, B. Sch"ottker, D. Schikora, and K. Lischka — Universit"at Paderborn, FB-6 Physik, Warburger Str. 100, D-33095 Paderborn

Under equilibrium conditions GaN crystallizes in the hexagonal structure. Recently, the growth conditions suitable for the preparation of metastable c-GaN-layers on GaAs-substrates by MBE have been established. In this work we report on spatially resolved cathodoluminescence (CL) spectroscopy of c-GaN-epilayers at 50 K and 300 K. The low- temperature CL spectra which were measured using scan areas of 50x50 µ m² at various positions on the epilayer surface were almost of equal intensity and show well separated lines at 3.26, 3.16 and 3.08 eV respectively. No emission above the band gap of the cubic phase at about 3.30 eV was detected using spatially and spectrally resolved CL-images. These our findings demonstrate the excellent homogeneity of our cubic epilayers. The room temperature cathodoluminescence shows one emission band peaked at about 3.20 eV with a full width of half maximum of about 75 meV which is to our knowledge the smallest halfwidth reported for the cathodoluminescence of cubic epilayers at room temperature so far.