Bi_(2)O_(2)Se/BP van der Waals heterojunction for high performance broadband photodetector

摘要

Broadband photodetector has wide applications in the field of remote sensing,health monitoring and medical imaging.Two-dimensional(2D)materials with narrow bandgaps have shown enormous potential in broadband photodetection.However,the device performance is often restricted by the high dark currents.Herein,we demonstrate a high performance broadband photodetector by constructing Bi2O2 Se/BP van der Waals heterojunction.The device exhibits a p-n diode behavior with a current rectification ratio of~20.Benifited from the low dark current of the heterojunction and the effective carrier separation,the device achieves the responsivity(R)of~500 A/W,~4.3 A/W and~2.3 A/W at 700 nm,1310 nm and 1550 nm,respectively.The specific detectivity(D^(*))is up to~2.8×10_(11)Jones(700 nm),~2.4×10_(9)Jones(1310 nm)and~1.3×10_(9)Jones(1550 nm).Moreover,the response time is~9 ms,which is more than 20 times faster than that of individual BP(~190 ms)and Bi_(2)O_(2)Se(~180 ms)devices.