Room temperature electro-optical and structural analysis were applied to study the origin of the defect-related absorption and emission in solar-blind AlGaN UV-photo-detectors grown by molecular beam epitaxy on c-plane sapphire and Si(111) substrates. Two resonance absorption peaks were observed in the photocurrent spectra for detectors grown on sapphire and Si substrates. Correlation of the peaks in the photocurrent and cathodoluminescence spectra, as well as their resonance character indicated that the resonance features related to the transitions, “deep level band” – “very shallow donor” with a depth of the order of the thermal energy (25-80meV).

Defect-Related Absorption and Emission in AlGaN Solar-Blind UV Photodetectors. V.Lebedev, I.Cimalla, V.Cimalla, R.Wagner, U.Kaiser, O.Ambacher: Physica Status Solidi C, 2005, 2[4], 1360-5