Growth and photocurrent property of GaN/anodic alumina/Si

Gallium nitride (GaN) epilayers were grown on Si(1 1 1) substrates using nearly polycrystalline α-Al2O3 as the buffer layer by low-pressure metal organic-chemical vapor deposition. The buffer was formed by anodic porous alumina annealed at high temperature. The scanning electron microscope measurement showed that the surface of GaN epilayer was smooth. Simple photoconductive detectors were fabricated with these materials. The spectral response of these detectors exhibited a relatively sharp cutoff near the wavelength of 360 nm and a peak at 340 nm with a shoulder near 360 nm. Under 5 V bias, the responsivities at 340 and 360 nm were measured to be 3.3 and 2.4 A/W respectively. [Copyright &y& Elsevier]