ZnO epitaxial films were grown on sapphire (0 0 0 1) substrates by using RF plasma-assisted molecular beam epitaxy (MBE). Metal-semiconductor-metal (MSM) ZnO photodiodes with palladium contact electrodes were then fabricated. With an incident wavelength of 370 nm and an applied bias of 1 V, it was found that maximum responsivity of the Pd/ZnO/Pd MSM photodetectors was 0.051 A W-1, which corresponds to a quantum efficiency of 11.4%. Furthermore, it was found that the time constant of our photodiodes was 24 ms with a three-order decay exponential function. For a given bandwidth of 100 Hz and an applied bias of 1 V, we found that noise equivalent power and corresponding detectivity D* were 1.13 × 10-12 W and 6.25 × 1011 cm Hz0.5 W-1, respectively.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys