Hot-electron photo­detectors show poor photo­electric performance due to the limitation of the small number and low energy of hot electrons. Traditional photo­transistors use elec­tricity to drive the transport of hot electrons and control photocurrent. However, the existence of defects leads to a slow response rate, voltage drive leads to a significant increase in dark current, and an electrical drive system is required.

In a new search, a team led by Fei Guangtao and Xu Shaohui from the Institute of Solid State Physics, Hefei Institutes of Physical Science, realized enhancement and fast stabili­zation of hot-electron photo­current of all-optical-input transistors with the regulation of ultraviolet light. “We introduced an ultraviolet light (gate light) to regulate the hot-electron photo­current, which is excited by infrared light (source light),” said Liu Shuli, “due to Schottky barrier-tuning effect and trap-filling effect, hot-electron photo­current in the Au electrode could be amplified tens of times, and response rate could also be improved.”

With the gate light increasing power, the enhanced photo­current reaches a stable state quickly. It is beneficial to understand and regulate the surface state of semi­conductors in opto­electronic fields. Considering that this type of transistor can work without electric support, it can be used in special environments that prohibit the use of elec­tricity. Moreover, this interesting feature will make devices more reliable and will meet the demands of energy-saving and low-carbon age. (Source: Hefei Inst. / CAS)

Reference: S. L. Liu et al.: All-Optical-Input Transistors with Light-Controlled Enhancement and Fast Stabilization of Hot-Electron Photocurrent, J. Phys. Chem. C 125, 18887 (2021); DOI: 10.1021/acs.jpcc.1c03364

Link: Institute of Solid State Physics, Institute of Physical Science and Information Technology, Anhui University, Hefei, China