Georgia Tech inventors have developed a zinc oxide (ZnO)-based UV light sensor to detect current flowing through a metal-oxide nanostructure. Their ZnO nanobelt sensor has been enhanced by 5 orders of magnitude by functionalizing its surface with a UV light-absorbing polymer. This increase in photoconductance is due to an electron-hole generation process assisted by the energy states in the polymer.
The devices were fabricated by aligning a ZnO nanobelt across two metal electrodes. A current source is configured to provide electrons to the first end of the metal-oxide nanostructure, and a current detector is used to detect the amount of current flowing through the structure. The amount of current flowing through the nanostructure corresponds to the amount of UV light impinging on the nanostructure.
- High sensitivity — The polymer coating increases the sensitivity of the UV detectors by 5 orders of magnitude.
- Large range — Different polymers can be used to functionalize the surface of the nanostructure, optimizing the detector for a wide array of wavelengths.
- Fast response speed — The combination of the polymer coating and ZnO nanobelts improves response speed and reset time
- Environmental monitoring
- Missile launch detection
- Space research
- High-temperature flame detection
- Optical communications
- Gas sensors
This technology was developed to provide highly selective and highly responsive photon detectors. Currently available silicon photodiode ultraviolet (UV) photon detectors are strongly influenced by visible light, and they usually require filters to attenuate unwanted visible and infrared (IR) radiation. For applications that require high sensitivity, silicon photodiodes need to be cooled to a low temperature to reduce the dark current.