UV detector based on an FTO/TiO2/MoO3 heterojunction with a potential well trapping electrons in the dark.

An FTO/TiO2/MoO3 based UV detector has been fabricated through the synthesis of TiO2 nanowires (NWs) on FTO using the hydrothermal method, the preparation of MoO3 on TiO2 NWs by the spin-coating method, after the hydrothermal synthesis, and the preparation of Ag electrodes on the FTO and MoO3. The detector exhibits an excellent performance of photo-to-dark current ratio of more than two orders of magnitude. This performance is produced because the dark current under 2.2 V bias has been significantly inhibited due to the electronic potential well formed by the energy band distribution while the photocurrent has increased in comparison with FTO/TiO2 based detectors under the same conditions which also have a higher photo-to-dark current ratio without the MoO3 content. Not only does this study take advantage of 1D NWs and 2D nanostructures, but it also provides a new way to inhibit the dark current of detectors.