Edge assisted epitaxy of CsPbBr_(3)nanoplates on Bi_(2)O_(2)Se nanosheets for enhanced photoresponse

Bi_(2)O_(2)Se has been proved to be a promising candidate for electronic and optoelectronic devices due to their unique physical properties.However,it is still a great challenge to construct the heterostructures with direct epitaxy of hetero semiconductor materials on Bi_(2)O_(2)Se nanosheets.Here,a two-step chemical vapor deposition(CVD)route was used to directly grow the CsPbBr_(3)nanoplate-Bi_(2)O_(2)Se nanosheet hetero structures.The CsPbBr_(3)nanoplates were selectively grown on the Bi_(2)O_(2)Se nanosheet along the edges,where the dangling bonds provide the nucleation sites.The epitaxial relationships between CsPbBr3 and Bi_(2)O_(2)Se were determined as[200]_(Bi_(2)O_(2)Se)‖[110]_(CsPbBr_(3))and[110]_(Bi_(2)O_(2)Se)‖[200]_(CsPbBr_(3))by transmission electron microscopy characterization.The photoluminescence(PL)results reveal that the formation of heterostructures results in the remarkable PL quenching due to the type-Ⅰband arrangement at CsPbBr_(3)/Bi_(2)O_(2)Se interface,which was confirmed by ultraviolet photoelectron spectroscopy(UPS)and Kelvin probe measurements,and makes the photogenerated carriers transfer from CsPbBr_(3)to Bi_(2)O_(2)Se.Importantly,the photodetectors based on the heterostructures exhibit a 4-time increase in the responsivity compared to those based on the pristine Bi_(2)O_(2)Se sheets,and the fast rise and decay time in microsecond.These results indicate that the direct epitaxy of the CsPbBr_(3)plates on the Bi_(2)O_(2)Se sheet may improve the optoelectronic performance of Bi_(2)O_(2)Se based devices.