Electrical characterization of transparent p-i-n heterojunction diodes

Transparent p-i-n heterojunction diodes are fabricated using heavily doped, p-type CuYO2 and semi-insulating i-ZnO thin films deposited onto a glass s ubstrate coated with n-type indium tin oxide. Rectification is observed, wi th a ratio of forward-to-reverse current as high as 60 in the range -4-4 V. The forward-bias current-voltage characteristics are dominated by the flow of space-charge-limited current, which is ascribed to single-carrier injec tion into the i-ZnO layer. Capacitance measurements show strong frequency d ispersion, which is attributed to i-ZnO traps. The diode structure has a to tal thickness of 0.75 mum and an optical transmission of similar to 35%-65% in the visible region. (C) 2001 American Institute of Physics.