Samples of Be-doped polycrystalline GaN film were deposited by means of the radio-frequency sputtering of a GaN/Be composite target onto fused silica substrates. The films were characterized by optical measurements, while microstructural information was obtained from scanning electron microscopy, atomic force microscopy and X-ray diffraction studies. Grain boundary parameters such as the density of trap states (Qt), and the barrier height (Eb) at the grain boundaries, were estimated from the broadening of the absorption tail. Photoluminescence measurement at 80K revealed 2 strong transitions, located at ~2.1eV and ~2.7eV, together with lower-intensity peaks for band-edge luminescence. These were ~3.47eV and 3.28eV, for films deposited at 423 and 623K, respectively.

Beryllium-Doped Polycrystalline GaN Films - Optical and Grain Boundary Properties. M.P.Chowdhury, R.K.Roy, B.R.Chakraborty, A.K.Pal: Thin Solid Films, 2005, 491[1-2], 29-37