Controllable preparation of TiO2 nanorod arrays for enhanced ultraviolet photoresponse performance of Au/TiO2 Schottky junction

Abstract

The optical and electrical properties of semiconductors depending on the microstructure are crucial for the application in various optoelectronic devices. TiO2 nanorod arrays (NRs) were prepared by hydrothermal method, and the ultraviolet (UV) photoresponse performance of Au/TiO2 NRs Schottky junction device was studied. The morphology, crystal orientation and filminess of TiO2 NRs were modulated by a facile control strategy employing anhydrous ethanol as stabilizer. With the increase of the amount of anhydrous ethanol, the diameter of TiO2 NR gradually expanded and the length increased rapidly. The anhydrous ethanol promotes the growth of TiO2 NRs preferentially in the [001] direction and decreases the oxygen vacancy in the surface of TiO2 NRs. With 10 mL of anhydrous ethanol added, the device displays a high sensitivity (8.93 A/W) to weak 376 nm UV light (0.18 mW/cm2) at a bias of -1V. The highest carrier concentration, the longest electron lifetime, the lowest interfacial charge transfer resistance and series resistance resulted in the best UV photoresponse. The exploration of dynamics process of photogenerated carriers in Schottky junction can help to improve the performance of optoelectronic devices such as photodetectors and solar cells.