Be-doped polycrystalline GaN films were deposited by radio frequency sputtering of a GaN/Be composite target onto fused silica substrates. The films were characterized by optical measurements, while the microstructural information was obtained from scanning electron microscopy, atomic force microscopy and X-ray diffraction studies. Grain boundary parameters like 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 exhibited 2 strong transitions located at about 2.1eV and about 2.7eV, along with lower intensity peaks for band-edge luminescence at about 3.47 and 3.28eV for films deposited at 423 and 623K, respectively.

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