Very low dark current metal-semiconductor-metal ultraviolet photodetectors fabricated on single-crystal GaN epitaxial layers

We report a very low dark current (similar to 57 pA at 10 V reverse bias) metal-semiconductor-metal photodetectors fabricated on GaN epitaxial layers grown by low-pressure metalorganic chemical vapor deposition. The photodetectors exhibit the typical sharp band-edge cutoff, with good responsivity. There is indication of a photoconductive gain mechanism. We also performed a Medici simulation to establish an effective area for current density calculations. (C) 1997 American Institute of Physics.