We have prepared large-area, 0.50×0.55 mm2, metal-semiconductor-metal photodetectors based on AlN layers with different density of inversion domains (IDs). AlN layers were grown on (0001) sapphire substrates using gas source molecular beam epitaxy. The introduction of AlN/GaN short period superlattices after growth of AlN nucleation layer yields significant reduction in the ID density. Photodetectors with ID density of 106 cm-2 exhibit a very low dark current of 0.5 fA at zero bias, which remains below 50 fA up to a bias of ±30 V. The peak responsivity of 0.08 A/W was obtained at a wavelength of ∼202 nm.
|Journal||Applied Physics Letters|
|State||Published - 2009|