AlxGa1-xN-based solar-blind ultraviolet photodetector based on lateral epitaxial overgrowth of AlN on Si substrate

We report on AlxGa1-xN-based solar-blind ultraviolet (UV) photodetector (PD) grown on Si(111) substrate. First, Si(111) substrate is patterned, and then metalorganic chemical vapor deposition is implemented for a fully-coalesced similar to 8.5 mu m AlN template layer via a pulsed atomic layer epitaxial growth technique. A back-illuminated p-i-n PD structure is subsequently grown on the high quality AlN template layer. After processing and implementation of Si(111) substrate removal, the optical and electrical characteristic of PDs are studied. Solar-blind operation is observed throughout the array; at the peak detection wavelength of 290 nm, 625 mu m(2) area PD showed unbiased peak external quantum efficiency and responsivity of similar to 7% and 18.3mA/W, respectively, with a UV and visible rejection ratio of more than three orders of magnitude. Electrical measurements yielded a low-dark current density below 1.6 x 10(-8) A/cm(2) at 10V reverse bias. (C) 2013 AIP Publishing LLC.