Transparent conducting polymer/n-GaN Schottky junction was fabricated in order to study deep level defects of III–V nitride films under light irradation. The leakage current was as low as 10−6 A cm−2 at reverse bias of 10 V. The Schottky barrier height reaches 1.15 eV under dark condition and under normalized solar spectrum AM1.5G the fill factor was up to 0.71 with an open-circuit voltage of 0.72 V and a short-circuit current of 0.37 mA cm−2. Deep level optical spectroscopy analysis revealed the presence of gallium vacancies (VGa) and/or related complexes impurities (VGa–ON and/or VGa–CN) at the interface between PEDOT:PSS and n-GaN. The Schottky and photovoltaic properties are discussed in term of deep level defects concentration.
Schematic illustration of PEDOT:PSS/III–V nitride Schottky junction with a metallic front grid on PEDOT:PSS layer.