Piezoelectric effect enhancing decay time of p-NiO/n-ZnO ultraviolet photodetector

- The decay time of the p-NiO/n-ZnO ultraviolet photodetector under various strains were investigated.
- The magnitude and the sign of the strain (tension/compression) have a great influence on the decay time by coupling piezoelectric and surface oxygen adsorption/desorption effects.
- This study gives an effective approach for designing and fabricating strain modulated fast reset UV photodetectors.

An ultraviolet photodetector based on p-NiO/n-ZnO heterojunction was fabricated using thermal oxidation and hydrothermal growth processes. The properties of the UV photoresponse under various strains were investigated. The results showed that the magnitude and the sign of the strain (tension/compression) have a great influence on the decay time by coupling piezoelectric and surface oxygen adsorption/desorption effects. These results demonstrate an effective approach for designing and fabricating strain modulated fast reset UV photodetectors.

The performances of the UV photodetectors can be optimized and significantly enhanced by introducing a piezo-phototronics effect to modify the depletion region and band structure of ZnO film surface.