Figures

Figure 1

Epitaxial layer structure of solar-blind AlGaN Schottky photodiode wafer.

Figure 2

Cross-section schematic of the fabricated AlGaN Schottky photodiode.

Figure 3

I-V characteristics of a 150x150 µm2 solar-blind Schottky photodiode. Inset shows the measured curve in logarithmic scale.

Figure 4

I-V measurement curve of a 200 µm diameter Schottky detector. Inset shows dark current versus UV photocurrent at 256 nm.

Figure 5

Spectral responsivity of the AlGaN Schottky photodiodes. A peak responsvity of 78 mA/W at 250 nm was obtained under 15 V reverse bias.

Figure 6

Bias-dependent spectral quantum efficiency curves of the solar-blind Schottky detector. A peak efficiency of 39% at 250 nm with a solar-blind cut-off at 266 nm was measured at 15 V.

Figure 7

Dark current noise power density of an 80 µm diameter high leakage Schottky photodiode at 1 Hz as a function of reverse bias.

Figure 8

Best pulse response measured with an 80 µm diameter device. Inset shows the FFT of temporal data. The AlGaN Schottky photodiode performed a 3-dB bandwidth of 870 MHz.

Figure 9

Pulse response of a 30 µm diameter solar-blind detector with 74 ps FWHM and 300 MHz 3-dB bandwidth. Inset shows the zoomed plot of the pulse response.

Figure 10

FFT curves of pulse responses from Schottky detectors with different device areas. 3-dB bandwidths of 220, 280, 510, and 780 MHz were obtained with decreasing device area.

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