Lateral epitaxial overgrowth of GaN on sapphire and silicon substrates forultraviolet photodetector applications

Lateral epitaxial overgrowth of GaN thin films was conducted by low-pressur e metalorganic chemical vapor deposition on basal plane sapphire and (111) silicon substrates. The films were characterized through X-ray diffraction, photoluminescence, scanning electron microscopy, atomic force microscopy a nd deep level transient spectroscopy. Schottky metal- semiconductor-metal u ltraviolet photodetectors were fabricated on LEO grown GaN films for the fi rst time. The spectral responsivity, its dependence on optical excitation p ower and bias voltage, and the device time decay properties were characteri zed. The orientation of the interdigitated lingers with respect to the LEO stripes was investigated. (C) 2000 Elsevier Science S.A. All rights reserve d.