Al_xGa_1?xN-based deep-ultraviolet 320×256 focal plane array

We report the synthesis, fabrication, and testing of a 320 × 256 focal plane array (FPA) of back-illuminated, solarblind, p-i-n, Al _xGa_1?xN-based detectors, fully realized within our research laboratory. We implemented a pulse atomic layer deposition technique for the metalorganic chemical vapor deposition growth of thick, high-quality, crack-free, high Al composition Al_xGa_1?xN layers. The FPA is hybridized to a matching ISC 9809 readout integrated circuit and operated in a SE-IR camera system. Solar-blind operation is observed throughout the array with peak detection occurring at wavelengths of 256 nm and lower, and falling off three orders of magnitude by ∼285 nm. By developing an opaque masking technology, the visible response of the ROIC is significantly reduced; thus the need for external filtering to achieve solar- and visible-blind operation is eliminated. This allows the FPA to achieve high external quantum efficiency (EQE); at 254 nm, average pixels showed unbiased peak responsivity of 75 mA?W, which corresponds to an EQE of ∼37%. Finally, the uniformity of the FPA and imaging properties are investigated.