Schottky barrier detectors on GaN for visible-blind ultraviolet detection

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 Schottky barrier metal. A responsitivity as high as 0.18 A/W was measured for wavelengths shorter than the absorption edge of GaN. The detector 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 the noise equivalent power at less than 4 x 10(-9) W. (C) 1997 American Institute of Physics.