We report on the fabrication and characterization of vertical geometry
transparent Schottky barrier ultraviolet detectors based on n(-)/n(+)
-GaN structures grown over sapphire substrates. Spectral responsivity
measurements were made using illumination through the UV transparent S
chottky barrier metal. A responsitivity as high as 0.18 A/W was measur
ed for wavelengths shorter than the absorption edge of GaN. The detect
or speed was RC limited and the fall time was 118 ns. The 1/f noise is
identified to be the main noise contribution. At 300 Hz, we measure t
he noise equivalent power at less than 4 x 10(-9) W. (C) 1997 American
Institute of Physics.