A surface photovoltaic effect-related high-performance photodetector based on a single CH3NH3PbI3 micro/nanowire

Abstract

With the decrease of materials to the nanoscale, their surface states will play a crucial role in their performance. Here, an individual CH₃NH₃PbI₃ micro/nanowire-based photodetector can show excellent sensitivity and responsivity to light with a wide wavelength range from 200 to 850 nm. A surface state-related photovoltaic effect is proposed. For the two-terminal devices, two back-to-back diodes associated with a surface barrier can be formed due to a depletion of majority carriers (holes) in the surface space charge region. At a low operation voltage, the photodetector can exhibit a low dark current. Upon illuminating near the end connected to the positive electrode, the light-induced decrease of the surface barrier leads to enhanced conduction, showing a large photocurrent. At zero bias, additionally, the photodetector can show a relatively large photogenerated voltage and current when only the vicinity of one end is illuminated. Based on the CH₃NH₃PbI₃ micro/nanostructure performance herein, surface photovoltaic-controlled photodetectors with superior performance will have important applications in new-generation optoelectronic devices.