doi:10.1038/nindia.2017.56 Published online 25 May 2017
Researchers have synthesized nanoflower-shaped structures of gallium nitride that can be used to make ultraviolet photodetectors1,to be used in the fields of space, military and biology as detectors and sensors.
Self-powered photodetectors produce current in the external circuit proportional to the intensity of incidental light, and detect optical signals. Their performance strongly depends on the material and active area of the device.Existing photodetectors made of silicon semiconductor cannot efficiently detect ultraviolet light.
To improve efficiency, scientists led by Govind Gupta from the CSIR-National Physical Laboratory in New Delhi made the photodetectors by depositing nanoflower-shaped gallium nitride ona silicon substrate. They then tested the photodetectors by bathing them in ultraviolet light.
The photodetectors exhibited increased light absorption which, in turn, created a light-induced current. The detectors were highly sensitive and showed fast response even when incident optical signals were weak.
Since the photodetectors did not rely on an external power source, they are energy-efficient and cheap to use.
“The photodetectors were able to detect ultraviolet light within milliseconds, making them potentially useful for monitoring solar ultraviolet light,” says Gupta.