Ultrahigh-Gain Single SnO2 Microrod Photoconductor on Flexible Substrate with Fast Recovery Speed

摘要

Owing to the special properties and wide applications, UV photodetectors based on wide-band-gap semiconductors have drawn an increasing interest during the last two decades. However, practical UV photodetectors are required two contradictory performances: high internal gain and fast recovery speed, because high internal gain is achieved by long life time of photoexcited carriers and fast recovery needs their fast decay. Their slow decay in wide-band-gap semiconductors has been known as a persistent photoconductivity (PPC) problem and hinders applications. In this paper, a good solution to the above contradictory problem is demonstrated on a single SnO2 microrod photoconductor, which shows both high photoconductive gain (approximate to 1.5 x 10(9)) and quick recovery speed (<1 s). Notably, the quick recovery speed is associated with the removal of the persistent photoconductivity effect (>1 d), which is induced by a novel reset process: bending and straightening the microrod and subsequently applying a voltage pulse. This result suggests that SnO2 microrods have potential applications in high-performance UV photodetecting devices.